kinokong
1.0.0
Proyek ini bootstrap dengan aplikasi Create React.
Di bawah ini Anda akan menemukan beberapa informasi tentang cara melakukan tugas umum.
Anda dapat menemukan versi terbaru dari panduan ini di sini.
<title>publicpublic.env<meta> di servernpm start tidak mendeteksi perubahannpm test Hang atau Crashes on Macos Sierranpm run build keluar terlalu dininpm run build Gagal di Herokunpm run build Gagal MinifyBuat aplikasi React dibagi menjadi dua paket:
create-react-app adalah utilitas baris perintah global yang Anda gunakan untuk membuat proyek baru.react-scripts adalah ketergantungan pengembangan dalam proyek yang dihasilkan (termasuk yang ini). Anda hampir tidak perlu memperbarui create-react-app sendiri: ia mendelegasikan semua pengaturan untuk react-scripts .
Saat Anda menjalankan create-react-app , itu selalu membuat proyek dengan versi terbaru dari react-scripts sehingga Anda akan mendapatkan semua fitur baru dan peningkatan dalam aplikasi yang baru dibuat secara otomatis.
Untuk memperbarui proyek yang ada ke versi baru react-scripts , buka Changelog, temukan versi yang sedang Anda gunakan (periksa package.json di folder ini jika Anda tidak yakin), dan terapkan instruksi migrasi untuk yang lebih baru versi.
Dalam kebanyakan kasus, menabrak versi react-scripts di package.json dan menjalankan npm install (atau yarn install ) di folder ini seharusnya cukup, tetapi ada baiknya berkonsultasi dengan changelog untuk potensi perubahan pemecahan.
Kami berkomitmen untuk menjaga perubahan minimal sehingga Anda dapat meningkatkan react-scripts tanpa rasa sakit.
Kami selalu terbuka untuk umpan balik Anda.
Setelah pembuatan, proyek Anda akan terlihat seperti ini:
my-app/
README.md
node_modules/
package.json
public/
index.html
favicon.ico
src/
App.css
App.js
App.test.js
index.css
index.js
logo.svg
Agar proyek dapat dibangun, file -file ini harus ada dengan nama file yang tepat :
public/index.html adalah templat halaman;src/index.js adalah titik masuk JavaScript.Anda dapat menghapus atau mengganti nama file lainnya.
Anda dapat membuat subdirektori di dalam src . Untuk pembangunan kembali yang lebih cepat, hanya file di dalam src yang diproses oleh Webpack.
Anda perlu meletakkan file JS dan CSS di dalam src , jika tidak, webpack tidak akan melihatnya.
Hanya file di dalam public yang dapat digunakan dari public/index.html .
Baca instruksi di bawah ini untuk menggunakan aset dari JavaScript dan HTML.
Namun, Anda dapat membuat lebih banyak direktori tingkat atas.
Mereka tidak akan dimasukkan dalam build produksi sehingga Anda dapat menggunakannya untuk hal -hal seperti dokumentasi.
Di direktori proyek, Anda dapat menjalankan:
npm start Menjalankan aplikasi dalam mode pengembangan.
Buka http: // localhost: 3000 untuk melihatnya di browser.
Halaman ini akan memuat ulang jika Anda mengedit.
Anda juga akan melihat kesalahan serat di konsol.
npm test Meluncurkan test runner dalam mode jam tangan interaktif.
Lihat bagian tentang menjalankan tes untuk informasi lebih lanjut.
npm run build Membangun aplikasi untuk produksi ke folder build .
Bundelnya dengan benar bereaksi dalam mode produksi dan mengoptimalkan build untuk kinerja terbaik.
Bangunan diminifikasi dan nama file termasuk hash.
Aplikasi Anda siap digunakan!
Lihat bagian tentang penyebaran untuk informasi lebih lanjut.
npm run eject Catatan: Ini adalah operasi satu arah. Setelah Anda eject , Anda tidak bisa kembali!
Jika Anda tidak puas dengan alat build dan pilihan konfigurasi, Anda dapat eject kapan saja. Perintah ini akan menghapus ketergantungan build tunggal dari proyek Anda.
Sebagai gantinya, itu akan menyalin semua file konfigurasi dan dependensi transitif (Webpack, Babel, Eslint, dll) langsung ke proyek Anda sehingga Anda memiliki kontrol penuh atasnya. Semua perintah kecuali eject masih akan berfungsi, tetapi mereka akan menunjuk ke skrip yang disalin sehingga Anda dapat mengubahnya. Pada titik ini Anda sendirian.
Anda tidak harus menggunakan eject . Set fitur yang dikuratori cocok untuk penyebaran kecil dan tengah, dan Anda tidak boleh merasa wajib menggunakan fitur ini. Namun kami memahami bahwa alat ini tidak akan berguna jika Anda tidak dapat menyesuaikannya saat Anda siap untuk itu.
Secara default, proyek yang dihasilkan mendukung semua browser modern.
Dukungan untuk Internet Explorer 9, 10, dan 11 membutuhkan polyfill.
Proyek ini mendukung superset standar JavaScript terbaru.
Selain fitur sintaks ES6, itu juga mendukung:
Pelajari lebih lanjut tentang berbagai tahap proposal.
Meskipun kami merekomendasikan penggunaan proposal eksperimental dengan hati -hati, Facebook banyak menggunakan fitur -fitur ini dalam kode produk, jadi kami bermaksud untuk memberikan codemods jika salah satu dari proposal ini berubah di masa depan.
Perhatikan bahwa proyek ini tidak mencakup Polyfills secara default.
Jika Anda menggunakan fitur ES6+ lain yang memerlukan dukungan runtime (seperti Array.from() atau Symbol ), pastikan Anda memasukkan polyfill yang sesuai secara manual, atau bahwa browser yang Anda targetkan sudah mendukungnya.
Untuk mengonfigurasi snector sintaks di editor teks favorit Anda, buka halaman dokumentasi Babel yang relevan dan ikuti instruksi. Beberapa editor paling populer tertutup.
Catatan: Fitur ini tersedia dengan
[email protected]dan lebih tinggi.
Ini juga hanya berfungsi dengan NPM 3 atau lebih tinggi.
Beberapa editor, termasuk teks luhur, atom, dan kode studio visual, menyediakan plugin untuk Eslint.
Mereka tidak diperlukan untuk berbaris. Anda akan melihat output linter tepat di terminal Anda serta konsol browser. Namun, jika Anda lebih suka hasil serat muncul tepat di editor Anda, ada beberapa langkah tambahan yang dapat Anda lakukan.
Anda perlu menginstal plugin Eslint untuk editor Anda terlebih dahulu. Kemudian, tambahkan file yang disebut .eslintrc ke root proyek:
{
"extends" : "react-app"
}Sekarang editor Anda harus melaporkan peringatan berberat.
Perhatikan bahwa bahkan jika Anda mengedit file .eslintrc Anda lebih lanjut, perubahan ini hanya akan mempengaruhi integrasi editor . Mereka tidak akan mempengaruhi output serat terminal dan in-browser. Ini karena Create React App secara sengaja memberikan seperangkat aturan minimal yang menemukan kesalahan umum.
Jika Anda ingin menegakkan gaya pengkodean untuk proyek Anda, pertimbangkan untuk menggunakan lebih cantik alih -alih aturan gaya Eslint.
Fitur ini saat ini hanya didukung oleh Visual Studio Code dan WebStorm.
Visual Studio Code dan Webstorm Dukungan Debugging Out of the Box dengan Aplikasi Create React. Ini memungkinkan Anda sebagai pengembang untuk menulis dan men -debug kode reaksi Anda tanpa meninggalkan editor, dan yang paling penting memungkinkan Anda untuk memiliki alur kerja pengembangan yang berkelanjutan, di mana pengalihan konteks minimal, karena Anda tidak harus beralih di antara alat.
Anda perlu memiliki versi terbaru dari VS Code dan VS Code Chrome Debugger Extension yang diinstal.
Kemudian tambahkan blok di bawah ini ke file launch.json Anda dan letakkan di dalam folder .vscode di direktori root aplikasi Anda.
{
"version" : " 0.2.0 " ,
"configurations" : [
{
"name" : " Chrome " ,
"type" : " chrome " ,
"request" : " launch " ,
"url" : " http://localhost:3000 " ,
"webRoot" : " ${workspaceRoot}/src " ,
"sourceMapPathOverrides" : {
"webpack:///src/*" : " ${webRoot}/* "
}
}
]
}Catatan: URL mungkin berbeda jika Anda telah melakukan penyesuaian melalui variabel host atau lingkungan port.
Mulai aplikasi Anda dengan menjalankan npm start , dan mulai men -debug dalam VS Code dengan menekan F5 atau dengan mengklik ikon Green Debug. Anda sekarang dapat menulis kode, mengatur breakpoint, membuat perubahan pada kode, dan men -debug kode yang baru dimodifikasi - semua dari editor Anda.
Memiliki masalah dengan debugging VS Code? Silakan lihat panduan pemecahan masalah mereka.
Anda perlu memiliki Webstorm dan JetBrains IDE mendukung ekstensi chrome terpasang.
Di menu Webstorm, Run pilih Edit Configurations... Kemudian klik + dan pilih JavaScript Debug . Tempel http://localhost:3000 ke dalam bidang URL dan simpan konfigurasi.
Catatan: URL mungkin berbeda jika Anda telah melakukan penyesuaian melalui variabel host atau lingkungan port.
Mulai aplikasi Anda dengan menjalankan npm start , lalu tekan ^D pada MacOS atau F9 di Windows dan Linux atau klik ikon Green Debug untuk memulai debugging di Webstorm.
Dengan cara yang sama Anda dapat men -debug aplikasi Anda di IntelliJ Idea Ultimate, PHPStorm, Pycharm Pro, dan Rubymine.
Prettier adalah formatter kode yang bertentangan dengan dukungan untuk JavaScript, CSS dan JSON. Dengan lebih cantik Anda dapat memformat kode yang Anda tulis secara otomatis untuk memastikan gaya kode dalam proyek Anda. Lihat halaman GitHub yang lebih cantik untuk informasi lebih lanjut, dan lihat halaman ini untuk melihatnya beraksi.
Untuk memformat kode kami setiap kali kami membuat komit di git, kami perlu menginstal ketergantungan berikut:
npm install --save husky lint-staged prettier Atau Anda dapat menggunakan yarn :
yarn add husky lint-staged prettierhusky memudahkan untuk menggunakan Githooks seolah -olah mereka adalah skrip NPM.lint-staged memungkinkan kita untuk menjalankan skrip pada file bertahap di git. Lihat posting blog ini tentang Lint-Stag untuk mempelajari lebih lanjut tentang itu.prettier adalah formatter JavaScript yang akan kami jalankan sebelum berkomitmen. Sekarang kita dapat memastikan setiap file diformat dengan benar dengan menambahkan beberapa baris ke package.json di root proyek.
Tambahkan bidang berikut ke bagian package.json :
+ "husky": {
+ "hooks": {
+ "pre-commit": "lint-staged"
+ }
+ } Selanjutnya kami menambahkan bidang 'bertahap' ke package.json , misalnya:
"dependencies": {
// ...
},
+ "lint-staged": {
+ "src/**/*.{js,jsx,json,css}": [
+ "prettier --single-quote --write",
+ "git add"
+ ]
+ },
"scripts": { Sekarang, setiap kali Anda membuat komit, lebih cantik akan memformat file yang diubah secara otomatis. Anda juga dapat menjalankan ./node_modules/.bin/prettier --single-quote --write "src/**/*.{js,jsx}" untuk memformat seluruh proyek Anda untuk pertama kalinya.
Selanjutnya Anda mungkin ingin mengintegrasikan lebih cantik dalam editor favorit Anda. Baca bagian tentang integrasi editor di halaman GitHub yang lebih cantik.
<title> Anda dapat menemukan file html sumber di folder public dari proyek yang dihasilkan. Anda dapat mengedit tag <title> di dalamnya untuk mengubah judul dari "React App" menjadi hal lain.
Perhatikan bahwa biasanya Anda tidak akan terlalu sering mengedit file di folder public . Misalnya, menambahkan stylesheet dilakukan tanpa menyentuh HTML.
Jika Anda perlu memperbarui judul halaman secara dinamis berdasarkan konten, Anda dapat menggunakan document.title Browser.Title API. Untuk skenario yang lebih kompleks ketika Anda ingin mengubah judul dari komponen React, Anda dapat menggunakan React Helmet, perpustakaan pihak ketiga.
Jika Anda menggunakan server khusus untuk aplikasi Anda dalam produksi dan ingin memodifikasi judul sebelum dikirim ke browser, Anda dapat mengikuti saran di bagian ini. Atau, Anda dapat pra-membangun setiap halaman sebagai file HTML statis yang kemudian memuat bundel JavaScript, yang dicakup di sini.
Proyek yang dihasilkan mencakup reaksi dan reaksi sebagai dependensi. Ini juga mencakup serangkaian skrip yang digunakan oleh Create React App sebagai ketergantungan pengembangan. Anda dapat menginstal dependensi lain (misalnya, reaksi router) dengan npm :
npm install --save react-router-dom Atau Anda dapat menggunakan yarn :
yarn add react-router-dom Ini berfungsi untuk perpustakaan mana pun, bukan hanya react-router-dom .
Pengaturan proyek ini mendukung modul ES6 berkat Webpack.
Meskipun Anda masih dapat menggunakan import require() dan module.exports export
Misalnya:
Button.js import React , { Component } from 'react' ;
class Button extends Component {
render ( ) {
// ...
}
}
export default Button ; // Don’t forget to use export default!DangerButton.js import React , { Component } from 'react' ;
import Button from './Button' ; // Import a component from another file
class DangerButton extends Component {
render ( ) {
return < Button color = "red" / > ;
}
}
export default DangerButton ;Waspadai perbedaan antara ekspor default dan yang disebutkan. Ini adalah sumber kesalahan yang umum.
Kami menyarankan agar Anda tetap menggunakan impor dan ekspor default ketika modul hanya mengekspor satu hal (misalnya, komponen). Itulah yang Anda dapatkan saat menggunakan export default Button dan import Button from './Button' .
Ekspor bernama berguna untuk modul utilitas yang mengekspor beberapa fungsi. Modul mungkin memiliki paling banyak satu ekspor default dan sebanyak banyak ekspor bernama yang Anda suka.
Pelajari lebih lanjut tentang modul ES6:
Alih -alih mengunduh seluruh aplikasi sebelum pengguna dapat menggunakannya, pemisahan kode memungkinkan Anda untuk membagi kode menjadi potongan -potongan kecil yang kemudian dapat Anda muat sesuai permintaan.
Pengaturan proyek ini mendukung pemisahan kode melalui Dynamic import() . Proposalnya ada di Tahap 3. Formulir seperti fungsi import() mengambil nama modul sebagai argumen dan mengembalikan Promise yang selalu diselesaikan ke objek namespace modul.
Inilah contohnya:
moduleA.js const moduleA = 'Hello' ;
export { moduleA } ;App.js import React , { Component } from 'react' ;
class App extends Component {
handleClick = ( ) => {
import ( './moduleA' )
. then ( ( { moduleA } ) => {
// Use moduleA
} )
. catch ( err => {
// Handle failure
} ) ;
} ;
render ( ) {
return (
< div >
< button onClick = { this . handleClick } > Load < / button >
< / div >
) ;
}
}
export default App ; Ini akan membuat moduleA.js dan semua dependensi uniknya sebagai potongan terpisah yang hanya memuat setelah pengguna mengklik tombol 'Muat'.
Anda juga dapat menggunakannya dengan sintaks async / await jika Anda lebih suka.
Jika Anda menggunakan react router, periksa tutorial ini tentang cara menggunakan kode pemisahan dengannya. Anda dapat menemukan repositori github pendamping di sini.
Periksa juga bagian pemisahan kode dalam dokumentasi React.
Pengaturan proyek ini menggunakan webpack untuk menangani semua aset. Webpack menawarkan cara khusus untuk "memperluas" konsep import di luar JavaScript. Untuk mengungkapkan bahwa file JavaScript tergantung pada file CSS, Anda perlu mengimpor CSS dari file JavaScript :
Button.css. Button {
padding : 20 px ;
}Button.js import React , { Component } from 'react' ;
import './Button.css' ; // Tell Webpack that Button.js uses these styles
class Button extends Component {
render ( ) {
// You can use them as regular CSS styles
return < div className = "Button" / > ;
}
}Ini tidak diperlukan untuk bereaksi tetapi banyak orang menganggap fitur ini nyaman. Anda dapat membaca tentang manfaat dari pendekatan ini di sini. Namun Anda harus menyadari bahwa ini membuat kode Anda kurang portabel untuk alat dan lingkungan build lainnya daripada Webpack.
Dalam pengembangan, mengekspresikan ketergantungan dengan cara ini memungkinkan gaya Anda untuk dimuat dengan cepat saat Anda mengeditnya. Dalam produksi, semua file CSS akan digabungkan ke dalam satu file .css yang diminifikasi dalam output build.
Jika Anda khawatir tentang menggunakan semantik khusus webpack, Anda dapat memasukkan semua CSS Anda langsung ke src/index.css . Itu masih akan diimpor dari src/index.js , tetapi Anda selalu dapat menghapus impor itu jika Anda kemudian bermigrasi ke alat build yang berbeda.
Catatan: Fitur ini tersedia dengan
[email protected]dan lebih tinggi.
Proyek ini mendukung modul CSS bersama dengan stylesheet reguler menggunakan [name].module.css File penamaan konvensi. Modul CSS memungkinkan pelingkupan CSS dengan secara otomatis membuat nama kelas unik dari format [filename]_[classname]__[hash] .
Kiat: Jika Anda ingin melakukan preprocess stylesheet dengan sass maka pastikan untuk mengikuti instruksi instalasi dan kemudian ubah ekstensi file stylesheet sebagai berikut:
[name].module.scssatau[name].module.sass.
Modul CSS memungkinkan Anda menggunakan nama kelas CSS yang sama di file yang berbeda tanpa khawatir tentang penamaan bentrokan. Pelajari lebih lanjut tentang modul CSS di sini.
Button.module.css. error {
background-color : red;
}another-stylesheet.css. error {
color : red;
}Button.js import React , { Component } from 'react' ;
import styles from './Button.module.css' ; // Import css modules stylesheet as styles
import './another-stylesheet.css' ; // Import regular stylesheet
class Button extends Component {
render ( ) {
// reference as a js object
return < button className = { styles . error } > Error Button < / button > ;
}
} Tidak ada bentrokan dari nama kelas .error lainnya
<!-- This button has red background but not red text -->
< button class =" Button_error_ax7yz " > </ div > Ini adalah fitur opsional. File <link> dan CSS reguler didukung sepenuhnya. Modul CSS dihidupkan untuk file yang diakhiri dengan ekstensi .module.css .
Catatan: Fitur ini tersedia dengan
[email protected]dan lebih tinggi.
Secara umum, kami menyarankan Anda tidak menggunakan kembali kelas CSS yang sama di berbagai komponen. Misalnya, alih -alih menggunakan komponen .Button CSS di <AcceptButton> dan <RejectButton> komponen, kami sarankan membuat komponen <Button> dengan gaya sendiri .Button , bahwa keduanya <AcceptButton> dan <RejectButton> render (tapi tidak mewarisi).
Mengikuti aturan ini sering membuat preprocessor CSS kurang berguna, karena fitur seperti mixin dan bersarang digantikan oleh komposisi komponen. Namun, Anda dapat mengintegrasikan preprocessor CSS jika Anda merasa berharga.
Untuk menggunakan sass, pertama instal node-sass :
$ npm install node-sass --save
$ # or
$ yarn add node-sass Sekarang Anda dapat mengganti nama src/App.css ke src/App.scss dan memperbarui src/App.js untuk mengimpor src/App.scss . File ini dan file lainnya akan dikompilasi secara otomatis jika diimpor dengan ekstensi .scss atau .sass .
Untuk berbagi variabel antara file SASS, Anda dapat menggunakan impor SASS. Misalnya, src/App.scss dan file gaya komponen lainnya dapat mencakup @import "./shared.scss"; dengan definisi variabel.
Ini akan memungkinkan Anda melakukan impor seperti
@import ' styles/_colors.scss ' ; // assuming a styles directory under src/
@import ' ~nprogress/nprogress ' ; // importing a css file from the nprogress node moduleTip: Anda dapat memilih untuk menggunakan fitur ini dengan modul CSS juga!
Catatan: Anda harus awalan impor dari
node_modulesdengan~seperti yang ditampilkan di atas.
Pengaturan proyek ini meminimalkan CSS Anda dan menambahkan awalan vendor secara otomatis melalui autoprefixer sehingga Anda tidak perlu mengkhawatirkannya.
Dukungan untuk fitur CSS baru seperti all properti, properti break , properti khusus, dan rentang kueri media secara otomatis dikelola untuk menambahkan dukungan untuk browser yang lebih lama.
Anda dapat menyesuaikan browser dukungan target Anda dengan menyesuaikan tombol browserslist dalam package.json .
Misalnya, ini:
. App {
display : flex;
flex-direction : row;
align-items : center;
}menjadi ini:
. App {
display : -webkit-box;
display : -ms-flexbox;
display : flex;
-webkit-box-orient : horizontal;
-webkit-box-direction : normal;
-ms-flex-direction : row;
flex-direction : row;
-webkit-box-align : center;
-ms-flex-align : center;
align-items : center;
}Jika Anda perlu menonaktifkan autoprefixing untuk beberapa alasan, ikuti bagian ini.
Prefixing tata letak kisi CSS dinonaktifkan secara default, tetapi tidak akan menelanjangi awalan manual. Jika Anda ingin ikut serta ke awalan kisi CSS, pertama-tama biasakan diri Anda tentang keterbatasannya.
Untuk mengaktifkan awalan kisi CSS, tambahkan /* autoprefixer grid: on */ ke bagian atas file CSS Anda.
Dengan Webpack, menggunakan aset statis seperti gambar dan font berfungsi serupa dengan CSS.
Anda dapat import file tepat di modul JavaScript . Ini memberi tahu WebPack untuk memasukkan file itu di bundel. Tidak seperti impor CSS, mengimpor file memberi Anda nilai string. Nilai ini adalah jalur akhir yang dapat Anda referensi dalam kode Anda, misalnya sebagai atribut src dari suatu gambar atau href tautan ke PDF.
Untuk mengurangi jumlah permintaan ke server, mengimpor gambar yang kurang dari 10.000 byte mengembalikan data URI alih -alih jalur. Ini berlaku untuk ekstensi file berikut: BMP, GIF, JPG, JPEG, dan PNG. File SVG dikecualikan karena #1153.
Inilah contohnya:
import React from 'react' ;
import logo from './logo.png' ; // Tell Webpack this JS file uses this image
console . log ( logo ) ; // /logo.84287d09.png
function Header ( ) {
// Import result is the URL of your image
return < img src = { logo } alt = "Logo" / > ;
}
export default Header ;Ini memastikan bahwa ketika proyek dibangun, Webpack akan memindahkan gambar dengan benar ke folder build, dan memberi kami jalur yang benar.
Ini berfungsi di CSS juga:
. Logo {
background-image : url (. / logo.png);
} Webpack menemukan semua referensi modul relatif dalam CSS (mereka mulai dengan ./ ) dan menggantinya dengan jalur akhir dari bundel yang dikompilasi. Jika Anda membuat kesalahan ketik atau secara tidak sengaja menghapus file penting, Anda akan melihat kesalahan kompilasi, seperti ketika Anda mengimpor modul JavaScript yang tidak ada. Nama file terakhir dalam bundel yang dikompilasi dihasilkan oleh Webpack dari hash konten. Jika konten file berubah di masa mendatang, Webpack akan memberikan nama yang berbeda dalam produksi sehingga Anda tidak perlu khawatir tentang caching aset jangka panjang.
Harap diperhatikan bahwa ini juga merupakan fitur khusus dari Webpack.
Tidak diperlukan untuk bereaksi tetapi banyak orang menikmatinya (dan React Native menggunakan mekanisme yang serupa untuk gambar).
Cara alternatif untuk menangani aset statis dijelaskan di bagian selanjutnya.
Catatan: Fitur ini tersedia dengan
[email protected]dan lebih tinggi.
Salah satu cara untuk menambahkan file SVG dijelaskan di bagian di atas. Anda juga dapat mengimpor SVG secara langsung sebagai komponen bereaksi. Anda dapat menggunakan salah satu dari dua pendekatan. Dalam kode Anda akan terlihat seperti ini:
import { ReactComponent as Logo } from './logo.svg' ;
const App = ( ) => (
< div >
{ /* Logo is an actual React component */ }
< Logo / >
< / div >
) ; Ini berguna jika Anda tidak ingin memuat SVG sebagai file terpisah. Jangan lupa kawat gigi keriting di impor! Nama impor ReactComponent adalah khusus dan memberi tahu Create React bahwa Anda menginginkan komponen bereaksi yang membuat SVG, bukan nama file.
publicCatatan: Fitur ini tersedia dengan
[email protected]dan lebih tinggi.
Folder public berisi file HTML sehingga Anda dapat mengubahnya, misalnya, untuk mengatur judul halaman. Tag <script> dengan kode yang dikompilasi akan ditambahkan ke dalamnya secara otomatis selama proses pembuatan.
Anda juga dapat menambahkan aset lain ke folder public .
Perhatikan bahwa kami biasanya mendorong Anda untuk import aset dalam file JavaScript sebagai gantinya. Misalnya, lihat bagian tentang menambahkan stylesheet dan menambahkan gambar dan font. Mekanisme ini memberikan sejumlah manfaat:
Namun ada lubang palka yang dapat Anda gunakan untuk menambahkan aset di luar sistem modul.
Jika Anda memasukkan file ke dalam folder public , itu tidak akan diproses oleh Webpack. Sebaliknya itu akan disalin ke folder build yang tidak tersentuh. Untuk merujuk aset di folder public , Anda perlu menggunakan variabel khusus yang disebut PUBLIC_URL .
Inside index.html , Anda dapat menggunakannya seperti ini:
< link rel =" shortcut icon " href =" %PUBLIC_URL%/favicon.ico " > Hanya file di dalam folder public yang dapat diakses oleh %PUBLIC_URL% awalan. Jika Anda perlu menggunakan file dari src atau node_modules , Anda harus menyalinnya di sana untuk secara eksplisit menentukan niat Anda untuk menjadikan file ini bagian dari build.
Saat Anda menjalankan npm run build , Buat Aplikasi React akan menggantikan %PUBLIC_URL% dengan jalur absolut yang benar sehingga proyek Anda berfungsi bahkan jika Anda menggunakan perutean sisi klien atau meng-hostnya di URL non-root.
Dalam kode JavaScript, Anda dapat menggunakan process.env.PUBLIC_URL untuk tujuan yang sama:
render ( ) {
// Note: this is an escape hatch and should be used sparingly!
// Normally we recommend using `import` for getting asset URLs
// as described in “Adding Images and Fonts” above this section.
return < img src = { process . env . PUBLIC_URL + '/img/logo.png' } / > ;
}Ingatlah kelemahan dari pendekatan ini:
public yang diproses atau dikemas.public Biasanya kami merekomendasikan mengimpor stylesheet, gambar, dan font dari JavaScript. Folder public berguna sebagai solusi untuk sejumlah kasus yang kurang umum:
manifest.webmanifest .pace.js di luar kode yang dibundel.<script> . Perhatikan bahwa jika Anda menambahkan <script> yang menyatakan variabel global, Anda juga perlu membaca bagian selanjutnya tentang menggunakannya.
Ketika Anda memasukkan skrip dalam file HTML yang mendefinisikan variabel global dan mencoba menggunakan salah satu variabel ini dalam kode, linter akan mengeluh karena tidak dapat melihat definisi variabel.
Anda dapat menghindari ini dengan membaca variabel global secara eksplisit dari objek window , misalnya:
const $ = window . $ ;Ini membuatnya jelas bahwa Anda menggunakan variabel global dengan sengaja daripada karena kesalahan ketik.
Atau, Anda dapat memaksa linter untuk mengabaikan garis apa pun dengan menambahkan // eslint-disable-line setelahnya.
Anda tidak harus menggunakan reactstrap bersama dengan React tetapi ini adalah perpustakaan populer untuk mengintegrasikan bootstrap dengan aplikasi React. Jika Anda membutuhkannya, Anda dapat mengintegrasikannya dengan Create React App dengan mengikuti langkah -langkah ini:
Instal ReactStrap dan Bootstrap dari NPM. ReactStrap tidak termasuk bootstrap CSS sehingga ini perlu dipasang juga:
npm install --save reactstrap bootstrap@4 Atau Anda dapat menggunakan yarn :
yarn add bootstrap@4 reactstrap Impor Bootstrap CSS dan Tema Bootstrap Opsi Bootstrap CSS di awal file src/index.js Anda:
import 'bootstrap/dist/css/bootstrap.css' ;
// Put any other imports below so that CSS from your
// components takes precedence over default styles. Impor komponen reactstrap yang diperlukan dalam file src/App.js atau file komponen khusus Anda:
import { Button } from 'reactstrap' ; Sekarang Anda siap menggunakan komponen reactstrap impor dalam hierarki komponen Anda yang ditentukan dalam metode render. Berikut adalah contoh App.js yang diulang menggunakan reactstrap.
Catatan: Fitur ini tersedia dengan
[email protected]dan lebih tinggi.
Terkadang Anda mungkin perlu mengubah gaya visual bootstrap (atau paket setara).
Pada [email protected] Anda dapat mengimpor file .scss . Ini memungkinkan untuk menggunakan variabel SASS bawaan paket untuk preferensi gaya global.
Untuk menyesuaikan bootstrap, buat file yang disebut src/custom.scss (atau serupa) dan impor stylesheet sumber bootstrap. Tambahkan overrides sebelum file yang diimpor. Anda dapat merujuk dokumentasi Bootstrap untuk nama -nama variabel yang tersedia.
// Override default variables before the import
$body-bg : #000 ;
// Import Bootstrap and its default variables
@import ' ~bootstrap/scss/bootstrap.scss ' ;Catatan: Anda harus awalan impor dari
node_modulesdengan~seperti yang ditampilkan di atas.
Akhirnya, impor file .scss yang baru dibuat alih -alih bootstrap default .css di awal file src/index.js Anda, misalnya:
import './custom.scss' ; Flow adalah tipe checker statis yang membantu Anda menulis kode dengan lebih sedikit bug. Lihat pengantar ini untuk menggunakan tipe statis di JavaScript jika Anda baru dalam konsep ini.
Versi kerja aliran terbaru dengan Proyek Aplikasi React Create Out of the Box.
Untuk menambah aliran ke proyek aplikasi React, ikuti langkah -langkah ini:
npm install --save flow-bin (atau yarn add flow-bin )."flow": "flow" ke bagian scripts package.json Anda.json.npm run flow init (atau yarn flow init ) untuk membuat file .flowconfig di direktori root.// @flow ke file apa pun yang ingin Anda ketik periksa (misalnya, ke src/App.js ). Sekarang Anda dapat menjalankan npm run flow (atau yarn flow ) untuk memeriksa file untuk jenis kesalahan. Anda secara opsional dapat menggunakan IDE seperti nuclide untuk pengalaman terintegrasi yang lebih baik. Di masa depan kami berencana untuk mengintegrasikannya ke dalam Create React App bahkan lebih dekat.
Untuk mempelajari lebih lanjut tentang aliran, lihat dokumentasinya.
Relai adalah kerangka kerja untuk membangun aplikasi bereaksi berbasis data yang ditenagai oleh GraphQL. Kandidat rilis Relay Works saat ini dengan Proyek Aplikasi Buat React di luar kotak menggunakan Babel Macro. Cukup atur proyek Anda seperti yang ditetapkan dalam dokumentasi relai, lalu pastikan Anda memiliki versi plugin Babel yang menyediakan makro.
Untuk menambahkannya, jalankan:
npm install --save --dev babel-plugin-relay@dev Atau Anda dapat menggunakan yarn :
yarn upgrade babel-plugin-relay@dev Lalu, di mana pun Anda menggunakan tag Template graphql , impor makro:
import graphql from 'babel-plugin-relay/macro' ;
// instead of:
// import { graphql } from "babel-plugin-relay"
graphql `
query UserQuery {
viewer {
id
}
}
` ;Untuk mempelajari lebih lanjut tentang Relay, lihat dokumentasinya.
Create React App tidak meresepkan solusi routing tertentu, tetapi React Router adalah yang paling populer.
Untuk menambahkannya, jalankan:
npm install --save react-router-dom Atau Anda dapat menggunakan yarn :
yarn add react-router-dom Untuk mencobanya, hapus semua kode di src/App.js dan gantilah dengan salah satu contoh di situs webnya. Contoh dasar adalah tempat yang baik untuk memulai.
Perhatikan bahwa Anda mungkin perlu mengkonfigurasi server produksi Anda untuk mendukung perutean sisi klien sebelum menggunakan aplikasi Anda.
Catatan: Fitur ini tersedia dengan
[email protected]dan lebih tinggi.
Proyek Anda dapat mengkonsumsi variabel yang dinyatakan di lingkungan Anda seolah -olah mereka dinyatakan secara lokal di file JS Anda. Secara default, Anda akan memiliki NODE_ENV yang ditentukan untuk Anda, dan variabel lingkungan lainnya yang dimulai dengan REACT_APP_ .
Variabel lingkungan tertanam selama waktu pembangunan . Karena aplikasi Create React menghasilkan bundel HTML/CSS/JS statis, tidak mungkin membacanya saat runtime. Untuk membacanya saat runtime, Anda perlu memuat HTML ke dalam memori di server dan mengganti placeholder di runtime, seperti yang dijelaskan di sini. Atau Anda dapat membangun kembali aplikasi di server kapan saja Anda mengubahnya.
Catatan: Anda harus membuat variabel lingkungan khusus yang dimulai dengan
REACT_APP_. Setiap variabel lain kecualiNODE_ENVakan diabaikan untuk menghindari secara tidak sengaja memperlihatkan kunci pribadi pada mesin yang dapat memiliki nama yang sama. Mengubah variabel lingkungan apa pun akan mengharuskan Anda untuk memulai kembali server pengembangan jika berjalan.
Variabel lingkungan ini akan didefinisikan untuk Anda di process.env . Misalnya, memiliki variabel lingkungan bernama REACT_APP_SECRET_CODE akan diekspos di js Anda sebagai process.env.REACT_APP_SECRET_CODE .
Ada juga variabel lingkungan bawaan khusus yang disebut NODE_ENV . Anda dapat membacanya dari process.env.NODE_ENV . Saat Anda menjalankan npm start , itu selalu sama dengan 'development' , saat Anda menjalankan npm test selalu sama dengan 'test' , dan ketika Anda menjalankan npm run build untuk membuat bundel produksi, itu selalu sama dengan 'production' . Anda tidak dapat mengganti NODE_ENV secara manual. Ini mencegah pengembang secara tidak sengaja mengerahkan pembangunan yang lambat untuk produksi.
Variabel lingkungan ini dapat berguna untuk menampilkan informasi secara kondisional berdasarkan di mana proyek digunakan atau mengonsumsi data sensitif yang hidup di luar kontrol versi.
Pertama, Anda perlu memiliki variabel lingkungan yang ditentukan. Misalnya, katakanlah Anda ingin mengkonsumsi rahasia yang ditentukan dalam lingkungan di dalam <form> :
render ( ) {
return (
< div >
< small > You are running this application in < b > { process . env . NODE_ENV } < / b > mode. < / small >
< form >
< input type = "hidden" defaultValue = { process . env . REACT_APP_SECRET_CODE } / >
< / form >
< / div >
) ;
} Selama build, process.env.REACT_APP_SECRET_CODE akan diganti dengan nilai saat ini dari variabel lingkungan REACT_APP_SECRET_CODE . Ingatlah bahwa variabel NODE_ENV akan ditetapkan untuk Anda secara otomatis.
Saat Anda memuat aplikasi di browser dan memeriksa <input> , Anda akan melihat nilainya diatur ke abcdef , dan teks tebal akan menunjukkan lingkungan yang disediakan saat menggunakan npm start :
< div >
< small > You are running this application in < b > development </ b > mode. </ small >
< form >
< input type =" hidden " value =" abcdef " />
</ form >
</ div > Formulir di atas mencari variabel yang disebut REACT_APP_SECRET_CODE dari lingkungan. Untuk mengkonsumsi nilai ini, kita perlu mendefinisikannya di lingkungan. Ini dapat dilakukan dengan menggunakan dua cara: baik di shell Anda atau di file .env . Kedua cara ini dijelaskan dalam beberapa bagian berikutnya.
Memiliki akses ke NODE_ENV juga berguna untuk melakukan tindakan secara kondisional:
if ( process . env . NODE_ENV !== 'production' ) {
analytics . disable ( ) ;
} Saat Anda mengkompilasi aplikasi dengan npm run build , langkah minifikasi akan menghapus kondisi ini, dan bundel yang dihasilkan akan lebih kecil.
Catatan: Fitur ini tersedia dengan
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Anda juga dapat mengakses variabel lingkungan yang dimulai dengan REACT_APP_ di public/index.html . Misalnya:
< title > %REACT_APP_WEBSITE_NAME% </ title >Perhatikan bahwa peringatan dari bagian di atas berlaku:
NODE_ENV dan PUBLIC_URL ), nama variabel harus dimulai dengan REACT_APP_ untuk bekerja.Menentukan variabel lingkungan dapat bervariasi antara OS. Penting juga untuk mengetahui bahwa cara ini bersifat sementara untuk kehidupan sesi shell.
set " REACT_APP_SECRET_CODE = abcdef " && npm start(Catatan: Kutipan di sekitar penugasan variabel diperlukan untuk menghindari whitespace trailing.)
( $ env: REACT_APP_SECRET_CODE = " abcdef " ) -and (npm start)REACT_APP_SECRET_CODE=abcdef npm start.envCatatan: Fitur ini tersedia dengan
[email protected]dan lebih tinggi.
Untuk mendefinisikan variabel lingkungan permanen, buat file yang disebut .env di akar proyek Anda:
REACT_APP_SECRET_CODE=abcdef
Catatan: Anda harus membuat variabel lingkungan khusus yang dimulai dengan
REACT_APP_. Setiap variabel lain kecualiNODE_ENVakan diabaikan untuk menghindari secara tidak sengaja memperlihatkan kunci pribadi pada mesin yang dapat memiliki nama yang sama. Mengubah variabel lingkungan apa pun akan mengharuskan Anda untuk memulai kembali server pengembangan jika berjalan.
File .env harus diperiksa ke kontrol sumber (dengan pengecualian .env*.local ).
.env files can be used?Note: this feature is available with
[email protected]and higher .
.env : Default..env.local : Local overrides. This file is loaded for all environments except test..env.development , .env.test , .env.production : Environment-specific settings..env.development.local , .env.test.local , .env.production.local : Local overrides of environment-specific settings.Files on the left have more priority than files on the right:
npm start : .env.development.local , .env.development , .env.local , .envnpm run build : .env.production.local , .env.production , .env.local , .envnpm test : .env.test.local , .env.test , .env (note .env.local is missing) These variables will act as the defaults if the machine does not explicitly set them.
Please refer to the dotenv documentation for more details.
Note: If you are defining environment variables for development, your CI and/or hosting platform will most likely need these defined as well. Consult their documentation how to do this. For example, see the documentation for Travis CI or Heroku.
.envNote: this feature is available with
[email protected]and higher.
Expand variables already on your machine for use in your .env file (using dotenv-expand).
For example, to get the environment variable npm_package_version :
REACT_APP_VERSION=$npm_package_version
# also works:
# REACT_APP_VERSION=${npm_package_version}
Or expand variables local to the current .env file:
DOMAIN=www.example.com
REACT_APP_FOO=$DOMAIN/foo
REACT_APP_BAR=$DOMAIN/bar
Some popular libraries use decorators in their documentation.
Create React App intentionally doesn't support decorator syntax at the moment because:
However in many cases you can rewrite decorator-based code without decorators just as fine.
Please refer to these two threads for reference:
Create React App will add decorator support when the specification advances to a stable stage.
React doesn't prescribe a specific approach to data fetching, but people commonly use either a library like axios or the fetch() API provided by the browser.
The global fetch function allows you to easily make AJAX requests. It takes in a URL as an input and returns a Promise that resolves to a Response object. You can find more information about fetch here.
A Promise represents the eventual result of an asynchronous operation, you can find more information about Promises here and here. Both axios and fetch() use Promises under the hood. You can also use the async / await syntax to reduce the callback nesting.
Make sure the fetch() API and Promises are available in your target audience's browsers. For example, support in Internet Explorer requires a polyfill.
You can learn more about making AJAX requests from React components in the FAQ entry on the React website.
These tutorials will help you to integrate your app with an API backend running on another port, using fetch() to access it.
Check out this tutorial. You can find the companion GitHub repository here.
Check out this tutorial. You can find the companion GitHub repository here.
API Platform is a framework designed to build API-driven projects. It allows to create hypermedia and GraphQL APIs in minutes. It is shipped with an official Progressive Web App generator as well as a dynamic administration interface, both built for Create React App. Check out this tutorial.
Note: this feature is available with
[email protected]and higher.
People often serve the front-end React app from the same host and port as their backend implementation.
For example, a production setup might look like this after the app is deployed:
/ - static server returns index.html with React app
/todos - static server returns index.html with React app
/api/todos - server handles any /api/* requests using the backend implementation
Such setup is not required. However, if you do have a setup like this, it is convenient to write requests like fetch('/api/todos') without worrying about redirecting them to another host or port during development.
To tell the development server to proxy any unknown requests to your API server in development, add a proxy field to your package.json , for example:
"proxy" : "http://localhost:4000" , This way, when you fetch('/api/todos') in development, the development server will recognize that it's not a static asset, and will proxy your request to http://localhost:4000/api/todos as a fallback. The development server will only attempt to send requests without text/html in its Accept header to the proxy.
Conveniently, this avoids CORS issues and error messages like this in development:
Fetch API cannot load http://localhost:4000/api/todos. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
Keep in mind that proxy only has effect in development (with npm start ), and it is up to you to ensure that URLs like /api/todos point to the right thing in production. You don't have to use the /api prefix. Any unrecognized request without a text/html accept header will be redirected to the specified proxy .
The proxy option supports HTTP, HTTPS and WebSocket connections.
If the proxy option is not flexible enough for you, alternatively you can:
When you enable the proxy option, you opt into a more strict set of host checks. This is necessary because leaving the backend open to remote hosts makes your computer vulnerable to DNS rebinding attacks. The issue is explained in this article and this issue.
This shouldn't affect you when developing on localhost , but if you develop remotely like described here, you will see this error in the browser after enabling the proxy option:
Invalid Host header
To work around it, you can specify your public development host in a file called .env.development in the root of your project:
HOST=mypublicdevhost.com
If you restart the development server now and load the app from the specified host, it should work.
If you are still having issues or if you're using a more exotic environment like a cloud editor, you can bypass the host check completely by adding a line to .env.development.local . Note that this is dangerous and exposes your machine to remote code execution from malicious websites:
# NOTE: THIS IS DANGEROUS!
# It exposes your machine to attacks from the websites you visit.
DANGEROUSLY_DISABLE_HOST_CHECK=true
We don't recommend this approach.
Note: this feature is available with
[email protected]and higher.
If the proxy option is not flexible enough for you, you can get direct access to the Express app instance and hook up your own proxy middleware.
You can use this feature in conjunction with the proxy property in package.json , but it is recommended you consolidate all of your logic into src/setupProxy.js .
First, install http-proxy-middleware using npm or Yarn:
$ npm install http-proxy-middleware --save
$ # or
$ yarn add http-proxy-middleware Next, create src/setupProxy.js and place the following contents in it:
const proxy = require ( 'http-proxy-middleware' ) ;
module . exports = function ( app ) {
// ...
} ; You can now register proxies as you wish! Here's an example using the above http-proxy-middleware :
const proxy = require ( 'http-proxy-middleware' ) ;
module . exports = function ( app ) {
app . use ( proxy ( '/api' , { target : 'http://localhost:5000/' } ) ) ;
} ;Note: You do not need to import this file anywhere. It is automatically registered when you start the development server.
Note: This file only supports Node's JavaScript syntax. Be sure to only use supported language features (ie no support for Flow, ES Modules, etc).
Note: Passing the path to the proxy function allows you to use globbing and/or pattern matching on the path, which is more flexible than the express route matching.
Note: this feature is available with
[email protected]and higher.
You may require the dev server to serve pages over HTTPS. One particular case where this could be useful is when using the "proxy" feature to proxy requests to an API server when that API server is itself serving HTTPS.
To do this, set the HTTPS environment variable to true , then start the dev server as usual with npm start :
set HTTPS = true && npm start(Note: the lack of whitespace is intentional.)
( $ env: HTTPS = $true ) -and (npm start)HTTPS=true npm startNote that the server will use a self-signed certificate, so your web browser will almost definitely display a warning upon accessing the page.
<meta> Tags on the Server Since Create React App doesn't support server rendering, you might be wondering how to make <meta> tags dynamic and reflect the current URL. To solve this, we recommend to add placeholders into the HTML, like this:
<!doctype html >
< html lang =" en " >
< head >
< meta property =" og:title " content =" __OG_TITLE__ " >
< meta property =" og:description " content =" __OG_DESCRIPTION__ " > Then, on the server, regardless of the backend you use, you can read index.html into memory and replace __OG_TITLE__ , __OG_DESCRIPTION__ , and any other placeholders with values depending on the current URL. Just make sure to sanitize and escape the interpolated values so that they are safe to embed into HTML!
If you use a Node server, you can even share the route matching logic between the client and the server. However duplicating it also works fine in simple cases.
If you're hosting your build with a static hosting provider you can use react-snapshot or react-snap to generate HTML pages for each route, or relative link, in your application. These pages will then seamlessly become active, or “hydrated”, when the JavaScript bundle has loaded.
There are also opportunities to use this outside of static hosting, to take the pressure off the server when generating and caching routes.
The primary benefit of pre-rendering is that you get the core content of each page with the HTML payload—regardless of whether or not your JavaScript bundle successfully downloads. It also increases the likelihood that each route of your application will be picked up by search engines.
You can read more about zero-configuration pre-rendering (also called snapshotting) here.
Similarly to the previous section, you can leave some placeholders in the HTML that inject global variables, for example:
< ! doctype html >
< html lang = "en" >
< head >
< script >
window.SERVER_DATA = __SERVER_DATA__;
< / script > Then, on the server, you can replace __SERVER_DATA__ with a JSON of real data right before sending the response. The client code can then read window.SERVER_DATA to use it. Make sure to sanitize the JSON before sending it to the client as it makes your app vulnerable to XSS attacks.
Note: this feature is available with
[email protected]and higher.
Read the migration guide to learn how to enable it in older projects!
Create React App uses Jest as its test runner. To prepare for this integration, we did a major revamp of Jest so if you heard bad things about it years ago, give it another try.
Jest is a Node-based runner. This means that the tests always run in a Node environment and not in a real browser. This lets us enable fast iteration speed and prevent flakiness.
While Jest provides browser globals such as window thanks to jsdom, they are only approximations of the real browser behavior. Jest is intended to be used for unit tests of your logic and your components rather than the DOM quirks.
We recommend that you use a separate tool for browser end-to-end tests if you need them. They are beyond the scope of Create React App.
Jest will look for test files with any of the following popular naming conventions:
.js suffix in __tests__ folders..test.js suffix..spec.js suffix. The .test.js / .spec.js files (or the __tests__ folders) can be located at any depth under the src top level folder.
We recommend to put the test files (or __tests__ folders) next to the code they are testing so that relative imports appear shorter. For example, if App.test.js and App.js are in the same folder, the test just needs to import App from './App' instead of a long relative path. Colocation also helps find tests more quickly in larger projects.
When you run npm test , Jest will launch in the watch mode. Every time you save a file, it will re-run the tests, just like npm start recompiles the code.
The watcher includes an interactive command-line interface with the ability to run all tests, or focus on a search pattern. It is designed this way so that you can keep it open and enjoy fast re-runs. You can learn the commands from the “Watch Usage” note that the watcher prints after every run:
By default, when you run npm test , Jest will only run the tests related to files changed since the last commit. This is an optimization designed to make your tests run fast regardless of how many tests you have. However it assumes that you don't often commit the code that doesn't pass the tests.
Jest will always explicitly mention that it only ran tests related to the files changed since the last commit. You can also press a in the watch mode to force Jest to run all tests.
Jest will always run all tests on a continuous integration server or if the project is not inside a Git or Mercurial repository.
To create tests, add it() (or test() ) blocks with the name of the test and its code. You may optionally wrap them in describe() blocks for logical grouping but this is neither required nor recommended.
Jest provides a built-in expect() global function for making assertions. A basic test could look like this:
import sum from './sum' ;
it ( 'sums numbers' , ( ) => {
expect ( sum ( 1 , 2 ) ) . toEqual ( 3 ) ;
expect ( sum ( 2 , 2 ) ) . toEqual ( 4 ) ;
} ) ; All expect() matchers supported by Jest are extensively documented here.
You can also use jest.fn() and expect(fn).toBeCalled() to create “spies” or mock functions.
There is a broad spectrum of component testing techniques. They range from a “smoke test” verifying that a component renders without throwing, to shallow rendering and testing some of the output, to full rendering and testing component lifecycle and state changes.
Different projects choose different testing tradeoffs based on how often components change, and how much logic they contain. If you haven't decided on a testing strategy yet, we recommend that you start with creating simple smoke tests for your components:
import React from 'react' ;
import ReactDOM from 'react-dom' ;
import App from './App' ;
it ( 'renders without crashing' , ( ) => {
const div = document . createElement ( 'div' ) ;
ReactDOM . render ( < App / > , div ) ;
} ) ; This test mounts a component and makes sure that it didn't throw during rendering. Tests like this provide a lot of value with very little effort so they are great as a starting point, and this is the test you will find in src/App.test.js .
When you encounter bugs caused by changing components, you will gain a deeper insight into which parts of them are worth testing in your application. This might be a good time to introduce more specific tests asserting specific expected output or behavior.
If you'd like to test components in isolation from the child components they render, we recommend using shallow() rendering API from Enzyme. To install it, run:
npm install --save enzyme enzyme-adapter-react-16 react-test-renderer Alternatively you may use yarn :
yarn add enzyme enzyme-adapter-react-16 react-test-rendererAs of Enzyme 3, you will need to install Enzyme along with an Adapter corresponding to the version of React you are using. (The examples above use the adapter for React 16.)
The adapter will also need to be configured in your global setup file:
src/setupTests.js import { configure } from 'enzyme' ;
import Adapter from 'enzyme-adapter-react-16' ;
configure ( { adapter : new Adapter ( ) } ) ;Note: Keep in mind that if you decide to "eject" before creating
src/setupTests.js, the resultingpackage.jsonfile won't contain any reference to it. Read here to learn how to add this after ejecting.
Now you can write a smoke test with it:
import React from 'react' ;
import { shallow } from 'enzyme' ;
import App from './App' ;
it ( 'renders without crashing' , ( ) => {
shallow ( < App / > ) ;
} ) ; Unlike the previous smoke test using ReactDOM.render() , this test only renders <App> and doesn't go deeper. For example, even if <App> itself renders a <Button> that throws, this test will pass. Shallow rendering is great for isolated unit tests, but you may still want to create some full rendering tests to ensure the components integrate correctly. Enzyme supports full rendering with mount() , and you can also use it for testing state changes and component lifecycle.
You can read the Enzyme documentation for more testing techniques. Enzyme documentation uses Chai and Sinon for assertions but you don't have to use them because Jest provides built-in expect() and jest.fn() for spies.
Here is an example from Enzyme documentation that asserts specific output, rewritten to use Jest matchers:
import React from 'react' ;
import { shallow } from 'enzyme' ;
import App from './App' ;
it ( 'renders welcome message' , ( ) => {
const wrapper = shallow ( < App / > ) ;
const welcome = < h2 > Welcome to React < / h2 > ;
// expect(wrapper.contains(welcome)).toBe(true);
expect ( wrapper . contains ( welcome ) ) . toEqual ( true ) ;
} ) ; All Jest matchers are extensively documented here.
Nevertheless you can use a third-party assertion library like Chai if you want to, as described below.
Additionally, you might find jest-enzyme helpful to simplify your tests with readable matchers. The above contains code can be written more simply with jest-enzyme.
expect ( wrapper ) . toContainReact ( welcome ) ; To enable this, install jest-enzyme :
npm install --save jest-enzyme Alternatively you may use yarn :
yarn add jest-enzyme Import it in src/setupTests.js to make its matchers available in every test:
import 'jest-enzyme' ; We recommend that you use expect() for assertions and jest.fn() for spies. If you are having issues with them please file those against Jest, and we'll fix them. We intend to keep making them better for React, supporting, for example, pretty-printing React elements as JSX.
However, if you are used to other libraries, such as Chai and Sinon, or if you have existing code using them that you'd like to port over, you can import them normally like this:
import sinon from 'sinon' ;
import { expect } from 'chai' ;and then use them in your tests like you normally do.
Note: this feature is available with
[email protected]and higher.
If your app uses a browser API that you need to mock in your tests or if you just need a global setup before running your tests, add a src/setupTests.js to your project. It will be automatically executed before running your tests.
Misalnya:
src/setupTests.js const localStorageMock = {
getItem : jest . fn ( ) ,
setItem : jest . fn ( ) ,
clear : jest . fn ( ) ,
} ;
global . localStorage = localStorageMock ;Note: Keep in mind that if you decide to "eject" before creating
src/setupTests.js, the resultingpackage.jsonfile won't contain any reference to it, so you should manually create the propertysetupTestFrameworkScriptFilein the configuration for Jest, something like the following:
"jest" : { // ... "setupTestFrameworkScriptFile" : "<rootDir>/src/setupTests.js" }
You can replace it() with xit() to temporarily exclude a test from being executed.
Similarly, fit() lets you focus on a specific test without running any other tests.
Jest has an integrated coverage reporter that works well with ES6 and requires no configuration.
Run npm test -- --coverage (note extra -- in the middle) to include a coverage report like this:
Note that tests run much slower with coverage so it is recommended to run it separately from your normal workflow.
The default Jest coverage configuration can be overridden by adding any of the following supported keys to a Jest config in your package.json.
Supported overrides:
collectCoverageFromcoverageReporterscoverageThresholdsnapshotSerializersExample package.json:
{
"name" : " your-package " ,
"jest" : {
"collectCoverageFrom" : [
" src/**/*.{js,jsx} " ,
" !<rootDir>/node_modules/ " ,
" !<rootDir>/path/to/dir/ "
],
"coverageThreshold" : {
"global" : {
"branches" : 90 ,
"functions" : 90 ,
"lines" : 90 ,
"statements" : 90
}
},
"coverageReporters" : [ " text " ],
"snapshotSerializers" : [ " my-serializer-module " ]
}
} By default npm test runs the watcher with interactive CLI. However, you can force it to run tests once and finish the process by setting an environment variable called CI .
When creating a build of your application with npm run build linter warnings are not checked by default. Like npm test , you can force the build to perform a linter warning check by setting the environment variable CI . If any warnings are encountered then the build fails.
Popular CI servers already set the environment variable CI by default but you can do this yourself too:
.travis.yml file to your git repository. language: node_js
node_js:
- 8
cache:
directories:
- node_modules
script:
- npm run build
- npm test
Follow this article to set up CircleCI with a Create React App project.
set CI = true && npm test set CI = true && npm run build(Note: the lack of whitespace is intentional.)
( $ env: CI = $true ) -and (npm test)( $ env: CI = $true ) -and (npm run build)CI=true npm test CI=true npm run buildThe test command will force Jest to run tests once instead of launching the watcher.
If you find yourself doing this often in development, please file an issue to tell us about your use case because we want to make watcher the best experience and are open to changing how it works to accommodate more workflows.
The build command will check for linter warnings and fail if any are found.
If you know that none of your tests depend on jsdom, you can safely set --env=node , and your tests will run faster:
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
- "test": "react-scripts test"
+ "test": "react-scripts test --env=node"To help you make up your mind, here is a list of APIs that need jsdom :
window and documentReactDOM.render()TestUtils.renderIntoDocument() (a shortcut for the above)mount() in EnzymeIn contrast, jsdom is not needed for the following APIs:
TestUtils.createRenderer() (shallow rendering)shallow() in EnzymeFinally, jsdom is also not needed for snapshot testing.
Snapshot testing is a feature of Jest that automatically generates text snapshots of your components and saves them on the disk so if the UI output changes, you get notified without manually writing any assertions on the component output. Read more about snapshot testing.
If you use Visual Studio Code, there is a Jest extension which works with Create React App out of the box. This provides a lot of IDE-like features while using a text editor: showing the status of a test run with potential fail messages inline, starting and stopping the watcher automatically, and offering one-click snapshot updates.
There are various ways to setup a debugger for your Jest tests. We cover debugging in Chrome and Visual Studio Code.
Note: debugging tests requires Node 8 or higher.
Add the following to the scripts section in your project's package.json
"scripts" : {
"test:debug" : " react-scripts --inspect-brk test --runInBand "
} Place debugger; statements in any test and run:
$ npm run test:debugThis will start running your Jest tests, but pause before executing to allow a debugger to attach to the process.
Open the following in Chrome
about:inspect
After opening that link, the Chrome Developer Tools will be displayed. Select inspect on your process and a breakpoint will be set at the first line of the react script (this is done simply to give you time to open the developer tools and to prevent Jest from executing before you have time to do so). Click the button that looks like a "play" button in the upper right hand side of the screen to continue execution. When Jest executes the test that contains the debugger statement, execution will pause and you can examine the current scope and call stack.
Note: the --runInBand cli option makes sure Jest runs test in the same process rather than spawning processes for individual tests. Normally Jest parallelizes test runs across processes but it is hard to debug many processes at the same time.
Debugging Jest tests is supported out of the box for Visual Studio Code.
Use the following launch.json configuration file:
{
"version": "0.2.0",
"configurations": [
{
"name": "Debug CRA Tests",
"type": "node",
"request": "launch",
"runtimeExecutable": "${workspaceRoot}/node_modules/.bin/react-scripts",
"args": [
"test",
"--runInBand",
"--no-cache"
],
"cwd": "${workspaceRoot}",
"protocol": "inspector",
"console": "integratedTerminal",
"internalConsoleOptions": "neverOpen"
}
]
}
Usually, in an app, you have a lot of UI components, and each of them has many different states. For an example, a simple button component could have following states:
Usually, it's hard to see these states without running a sample app or some examples.
Create React App doesn't include any tools for this by default, but you can easily add Storybook for React (source) or React Styleguidist (source) to your project. These are third-party tools that let you develop components and see all their states in isolation from your app .
You can also deploy your Storybook or style guide as a static app. This way, everyone in your team can view and review different states of UI components without starting a backend server or creating an account in your app.
Storybook is a development environment for React UI components. It allows you to browse a component library, view the different states of each component, and interactively develop and test components.
First, install the following npm package globally:
npm install -g @storybook/cliThen, run the following command inside your app's directory:
getstorybookAfter that, follow the instructions on the screen.
Learn more about React Storybook:
Styleguidist combines a style guide, where all your components are presented on a single page with their props documentation and usage examples, with an environment for developing components in isolation, similar to Storybook. In Styleguidist you write examples in Markdown, where each code snippet is rendered as a live editable playground.
First, install Styleguidist:
npm install --save react-styleguidist Alternatively you may use yarn :
yarn add react-styleguidist Then, add these scripts to your package.json :
"scripts": {
+ "styleguide": "styleguidist server",
+ "styleguide:build": "styleguidist build",
"start": "react-scripts start",Then, run the following command inside your app's directory:
npm run styleguideAfter that, follow the instructions on the screen.
Learn more about React Styleguidist:
Create React App doesn't provide any built-in functionality to publish a component to npm. If you're ready to extract a component from your project so other people can use it, we recommend moving it to a separate directory outside of your project and then using a tool like nwb to prepare it for publishing.
The production build has all the tools necessary to generate a first-class Progressive Web App, but the offline/cache-first behavior is opt-in only . By default, the build process will generate a service worker file, but it will not be registered, so it will not take control of your production web app.
In order to opt-in to the offline-first behavior, developers should look for the following in their src/index.js file:
// If you want your app to work offline and load faster, you can change
// unregister() to register() below. Note this comes with some pitfalls.
// Learn more about service workers: http://bit.ly/CRA-PWA
serviceWorker . unregister ( ) ; As the comment states, switching serviceWorker.unregister() to serviceWorker.register() will opt you in to using the service worker.
Offline-first Progressive Web Apps are faster and more reliable than traditional web pages, and provide an engaging mobile experience:
However, they can make debugging deployments more challenging so, starting with Create React App 2, service workers are opt-in.
The workbox-webpack-plugin is integrated into production configuration, and it will take care of generating a service worker file that will automatically precache all of your local assets and keep them up to date as you deploy updates. The service worker will use a cache-first strategy for handling all requests for local assets, including navigation requests for your HTML, ensuring that your web app is consistently fast, even on a slow or unreliable network.
If you do decide to opt-in to service worker registration, please take the following into account:
Service workers require HTTPS, although to facilitate local testing, that policy does not apply to localhost . If your production web server does not support HTTPS, then the service worker registration will fail, but the rest of your web app will remain functional.
Service workers are not supported in older web browsers. Service worker registration won't be attempted on browsers that lack support.
The service worker is only enabled in the production environment, eg the output of npm run build . It's recommended that you do not enable an offline-first service worker in a development environment, as it can lead to frustration when previously cached assets are used and do not include the latest changes you've made locally.
If you need to test your offline-first service worker locally, build the application (using npm run build ) and run a simple http server from your build directory. After running the build script, create-react-app will give instructions for one way to test your production build locally and the deployment instructions have instructions for using other methods. Be sure to always use an incognito window to avoid complications with your browser cache.
Users aren't always familiar with offline-first web apps. It can be useful to let the user know when the service worker has finished populating your caches (showing a "This web app works offline!" message) and also let them know when the service worker has fetched the latest updates that will be available the next time they load the page (showing a "New content is available; please refresh." message). Showing this messages is currently left as an exercise to the developer, but as a starting point, you can make use of the logic included in src/registerServiceWorker.js , which demonstrates which service worker lifecycle events to listen for to detect each scenario, and which as a default, just logs appropriate messages to the JavaScript console.
By default, the generated service worker file will not intercept or cache any cross-origin traffic, like HTTP API requests, images, or embeds loaded from a different domain.
The default configuration includes a web app manifest located at public/manifest.json , that you can customize with details specific to your web application.
When a user adds a web app to their homescreen using Chrome or Firefox on Android, the metadata in manifest.json determines what icons, names, and branding colors to use when the web app is displayed. The Web App Manifest guide provides more context about what each field means, and how your customizations will affect your users' experience.
Progressive web apps that have been added to the homescreen will load faster and work offline when there's an active service worker. That being said, the metadata from the web app manifest will still be used regardless of whether or not you opt-in to service worker registration.
Source map explorer analyzes JavaScript bundles using the source maps. This helps you understand where code bloat is coming from.
To add Source map explorer to a Create React App project, follow these steps:
npm install --save source-map-explorer Alternatively you may use yarn :
yarn add source-map-explorer Then in package.json , add the following line to scripts :
"scripts": {
+ "analyze": "source-map-explorer build/static/js/main.*",
"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",Then to analyze the bundle run the production build then run the analyze script.
npm run build
npm run analyze
npm run build creates a build directory with a production build of your app. Set up your favorite HTTP server so that a visitor to your site is served index.html , and requests to static paths like /static/js/main.<hash>.js are served with the contents of the /static/js/main.<hash>.js file.
For environments using Node, the easiest way to handle this would be to install serve and let it handle the rest:
npm install -g serve
serve -s build The last command shown above will serve your static site on the port 5000 . Like many of serve's internal settings, the port can be adjusted using the -p or --port flags.
Run this command to get a full list of the options available:
serve -hYou don't necessarily need a static server in order to run a Create React App project in production. It works just as fine integrated into an existing dynamic one.
Here's a programmatic example using Node and Express:
const express = require ( 'express' ) ;
const path = require ( 'path' ) ;
const app = express ( ) ;
app . use ( express . static ( path . join ( __dirname , 'build' ) ) ) ;
app . get ( '/' , function ( req , res ) {
res . sendFile ( path . join ( __dirname , 'build' , 'index.html' ) ) ;
} ) ;
app . listen ( 9000 ) ;The choice of your server software isn't important either. Since Create React App is completely platform-agnostic, there's no need to explicitly use Node.
The build folder with static assets is the only output produced by Create React App.
However this is not quite enough if you use client-side routing. Read the next section if you want to support URLs like /todos/42 in your single-page app.
If you use routers that use the HTML5 pushState history API under the hood (for example, React Router with browserHistory ), many static file servers will fail. For example, if you used React Router with a route for /todos/42 , the development server will respond to localhost:3000/todos/42 properly, but an Express serving a production build as above will not.
This is because when there is a fresh page load for a /todos/42 , the server looks for the file build/todos/42 and does not find it. The server needs to be configured to respond to a request to /todos/42 by serving index.html . For example, we can amend our Express example above to serve index.html for any unknown paths:
app.use(express.static(path.join(__dirname, 'build')));
- app.get('/', function (req, res) {
+ app.get('/*', function (req, res) {
res.sendFile(path.join(__dirname, 'build', 'index.html'));
}); If you're using Apache HTTP Server, you need to create a .htaccess file in the public folder that looks like this:
Options -MultiViews
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.html [QSA,L]
It will get copied to the build folder when you run npm run build .
If you're using Apache Tomcat, you need to follow this Stack Overflow answer.
Now requests to /todos/42 will be handled correctly both in development and in production.
On a production build, and when you've opted-in, a service worker will automatically handle all navigation requests, like for /todos/42 , by serving the cached copy of your index.html . This service worker navigation routing can be configured or disabled by eject ing and then modifying the navigateFallback and navigateFallbackWhitelist options of the SWPreachePlugin configuration.
When users install your app to the homescreen of their device the default configuration will make a shortcut to /index.html . This may not work for client-side routers which expect the app to be served from / . Edit the web app manifest at public/manifest.json and change start_url to match the required URL scheme, for example:
"start_url" : "." , By default, Create React App produces a build assuming your app is hosted at the server root.
To override this, specify the homepage in your package.json , for example:
"homepage" : "http://mywebsite.com/relativepath" ,This will let Create React App correctly infer the root path to use in the generated HTML file.
Note : If you are using react-router@^4 , you can root <Link> s using the basename prop on any <Router> .
More information here.
Misalnya:
< BrowserRouter basename = "/calendar" / >
< Link to = "/today" / > // renders <a href="/calendar/today"> Note: this feature is available with
[email protected]and higher.
If you are not using the HTML5 pushState history API or not using client-side routing at all, it is unnecessary to specify the URL from which your app will be served. Instead, you can put this in your package.json :
"homepage" : "." , This will make sure that all the asset paths are relative to index.html . You will then be able to move your app from http://mywebsite.com to http://mywebsite.com/relativepath or even http://mywebsite.com/relative/path without having to rebuild it.
You can create an arbitrary build environment by creating a custom .env file and loading it using env-cmd.
For example, to create a build environment for a staging environment:
.env.staging.env file (eg REACT_APP_API_URL=http://api-staging.example.com )$ npm install env-cmd --save
$ # or
$ yarn add env-cmdpackage.json , building with your new environment: {
"scripts" : {
"build:staging" : " env-cmd .env.staging npm run build "
}
} Now you can run npm run build:staging to build with the staging environment config. You can specify other environments in the same way.
Variables in .env.production will be used as fallback because NODE_ENV will always be set to production for a build.
See this blog post on how to deploy your React app to Microsoft Azure.
See this blog post or this repo for a way to use automatic deployment to Azure App Service.
Install the Firebase CLI if you haven't already by running npm install -g firebase-tools . Sign up for a Firebase account and create a new project. Run firebase login and login with your previous created Firebase account.
Then run the firebase init command from your project's root. You need to choose the Hosting: Configure and deploy Firebase Hosting sites and choose the Firebase project you created in the previous step. You will need to agree with database.rules.json being created, choose build as the public directory, and also agree to Configure as a single-page app by replying with y .
=== Project Setup
First, let ' s associate this project directory with a Firebase project.
You can create multiple project aliases by running firebase use --add,
but for now we ' ll just set up a default project.
? What Firebase project do you want to associate as default ? Example app (example-app-fd690)
=== Database Setup
Firebase Realtime Database Rules allow you to define how your data should be
structured and when your data can be read from and written to.
? What file should be used for Database Rules ? database.rules.json
✔ Database Rules for example-app-fd690 have been downloaded to database.rules.json.
Future modifications to database.rules.json will update Database Rules when you run
firebase deploy.
=== Hosting Setup
Your public directory is the folder (relative to your project directory) that
will contain Hosting assets to uploaded with firebase deploy. If you
have a build process for your assets, use your build ' s output directory.
? What do you want to use as your public directory? build
? Configure as a single-page app (rewrite all urls to /index.html)? Yes
✔ Wrote build/index.html
i Writing configuration info to firebase.json...
i Writing project information to .firebaserc...
✔ Firebase initialization complete! IMPORTANT: you need to set proper HTTP caching headers for service-worker.js file in firebase.json file or you will not be able to see changes after first deployment (issue #2440). It should be added inside "hosting" key like next:
{
"hosting": {
...
"headers": [
{"source": "/service-worker.js", "headers": [{"key": "Cache-Control", "value": "no-cache"}]}
]
...
Now, after you create a production build with npm run build , you can deploy it by running firebase deploy .
=== Deploying to ' example-app-fd690 ' ...
i deploying database, hosting
✔ database: rules ready to deploy.
i hosting: preparing build directory for upload...
Uploading: [ ============================== ] 75%✔ hosting: build folder uploaded successfully
✔ hosting: 8 files uploaded successfully
i starting release process (may take several minutes)...
✔ Deploy complete !
Project Console: https://console.firebase.google.com/project/example-app-fd690/overview
Hosting URL: https://example-app-fd690.firebaseapp.comFor more information see Add Firebase to your JavaScript Project.
Note: this feature is available with
[email protected]and higher.
homepage to package.json The step below is important!
If you skip it, your app will not deploy correctly.
Open your package.json and add a homepage field for your project:
"homepage" : " https://myusername.github.io/my-app " ,or for a GitHub user page:
"homepage" : " https://myusername.github.io " ,or for a custom domain page:
"homepage" : " https://mywebsite.com " , Create React App uses the homepage field to determine the root URL in the built HTML file.
gh-pages and add deploy to scripts in package.json Now, whenever you run npm run build , you will see a cheat sheet with instructions on how to deploy to GitHub Pages.
To publish it at https://myusername.github.io/my-app, run:
npm install --save gh-pages Alternatively you may use yarn :
yarn add gh-pages Add the following scripts in your package.json :
"scripts": {
+ "predeploy": "npm run build",
+ "deploy": "gh-pages -d build",
"start": "react-scripts start",
"build": "react-scripts build", The predeploy script will run automatically before deploy is run.
If you are deploying to a GitHub user page instead of a project page you'll need to make two additional modifications:
package.json scripts to push deployments to master : "scripts": {
"predeploy": "npm run build",
- "deploy": "gh-pages -d build",
+ "deploy": "gh-pages -b master -d build", npm run deployKemudian jalankan:
npm run deploygh-pages Finally, make sure GitHub Pages option in your GitHub project settings is set to use the gh-pages branch:
You can configure a custom domain with GitHub Pages by adding a CNAME file to the public/ folder.
Your CNAME file should look like this:
mywebsite.com
GitHub Pages doesn't support routers that use the HTML5 pushState history API under the hood (for example, React Router using browserHistory ). This is because when there is a fresh page load for a url like http://user.github.io/todomvc/todos/42 , where /todos/42 is a frontend route, the GitHub Pages server returns 404 because it knows nothing of /todos/42 . If you want to add a router to a project hosted on GitHub Pages, here are a couple of solutions:
hashHistory for this effect, but the URL will be longer and more verbose (for example, http://user.github.io/todomvc/#/todos/42?_k=yknaj ). Read more about different history implementations in React Router.index.html page with a special redirect parameter. You would need to add a 404.html file with the redirection code to the build folder before deploying your project, and you'll need to add code handling the redirect parameter to index.html . You can find a detailed explanation of this technique in this guide. If, when deploying, you get /dev/tty: No such a device or address or a similar error, try the following:
git remote set-url origin https://<user>:<token>@github.com/<user>/<repo> .npm run deploy again If, when deploying, you get Cannot read property 'email' of null , try the following:
git config --global user.name '<your_name>'git config --global user.email '<your_email>'npm run deploy again Use the Heroku Buildpack for Create React App.
You can find instructions in Deploying React with Zero Configuration.
Sometimes npm run build works locally but fails during deploy via Heroku. Following are the most common cases.
If you get something like this:
remote: Failed to create a production build. Reason:
remote: Module not found: Error: Cannot resolve 'file' or 'directory'
MyDirectory in /tmp/build_1234/src
It means you need to ensure that the lettercase of the file or directory you import matches the one you see on your filesystem or on GitHub.
This is important because Linux (the operating system used by Heroku) is case sensitive. So MyDirectory and mydirectory are two distinct directories and thus, even though the project builds locally, the difference in case breaks the import statements on Heroku remotes.
If you exclude or ignore necessary files from the package you will see a error similar this one:
remote: Could not find a required file.
remote: Name: `index.html`
remote: Searched in: /tmp/build_a2875fc163b209225122d68916f1d4df/public
remote:
remote: npm ERR! Linux 3.13.0-105-generic
remote: npm ERR! argv "/tmp/build_a2875fc163b209225122d68916f1d4df/.heroku/node/bin/node" "/tmp/build_a2875fc163b209225122d68916f1d4df/.heroku/node/bin/npm" "run" "build"
In this case, ensure that the file is there with the proper lettercase and that's not ignored on your local .gitignore or ~/.gitignore_global .
To do a manual deploy to Netlify's CDN:
npm install netlify-cli -g
netlify deploy Choose build as the path to deploy.
To setup continuous delivery:
With this setup Netlify will build and deploy when you push to git or open a pull request:
Build your siteSupport for client-side routing:
To support pushState , make sure to create a public/_redirects file with the following rewrite rules:
/* /index.html 200
When you build the project, Create React App will place the public folder contents into the build output.
Now offers a zero-configuration single-command deployment. You can use now to deploy your app for free.
Install the now command-line tool either via the recommended desktop tool or via node with npm install -g now .
Build your app by running npm run build .
Move into the build directory by running cd build .
Run now --name your-project-name from within the build directory. You will see a now.sh URL in your output like this:
> Ready! https://your-project-name-tpspyhtdtk.now.sh (copied to clipboard)
Paste that URL into your browser when the build is complete, and you will see your deployed app.
Details are available in this article.
See this blog post on how to deploy your React app to Amazon Web Services S3 and CloudFront.
Install the Surge CLI if you haven't already by running npm install -g surge . Run the surge command and log in you or create a new account.
When asked about the project path, make sure to specify the build folder, for example:
project path: /path/to/project/build Note that in order to support routers that use HTML5 pushState API, you may want to rename the index.html in your build folder to 200.html before deploying to Surge. This ensures that every URL falls back to that file.
You can adjust various development and production settings by setting environment variables in your shell or with .env.
| Variabel | Perkembangan | Produksi | Penggunaan |
|---|---|---|---|
| BROWSER | ✅ | By default, Create React App will open the default system browser, favoring Chrome on macOS. Specify a browser to override this behavior, or set it to none to disable it completely. If you need to customize the way the browser is launched, you can specify a node script instead. Any arguments passed to npm start will also be passed to this script, and the url where your app is served will be the last argument. Your script's file name must have the .js extension. | |
| TUAN RUMAH | ✅ | By default, the development web server binds to localhost . You may use this variable to specify a different host. | |
| PELABUHAN | ✅ | By default, the development web server will attempt to listen on port 3000 or prompt you to attempt the next available port. You may use this variable to specify a different port. | |
| Https | ✅ | When set to true , Create React App will run the development server in https mode. | |
| PUBLIC_URL | ✅ | Create React App assumes your application is hosted at the serving web server's root or a subpath as specified in package.json ( homepage ). Normally, Create React App ignores the hostname. You may use this variable to force assets to be referenced verbatim to the url you provide (hostname included). This may be particularly useful when using a CDN to host your application. | |
| CI | ? | ✅ | When set to true , Create React App treats warnings as failures in the build. It also makes the test runner non-watching. Most CIs set this flag by default. |
| REACT_EDITOR | ✅ | When an app crashes in development, you will see an error overlay with clickable stack trace. When you click on it, Create React App will try to determine the editor you are using based on currently running processes, and open the relevant source file. You can send a pull request to detect your editor of choice. Setting this environment variable overrides the automatic detection. If you do it, make sure your systems PATH environment variable points to your editor's bin folder. You can also set it to none to disable it completely. | |
| CHOKIDAR_USEPOLLING | ✅ | When set to true , the watcher runs in polling mode, as necessary inside a VM. Use this option if npm start isn't detecting changes. | |
| GENERATE_SOURCEMAP | ✅ | When set to false , source maps are not generated for a production build. This solves OOM issues on some smaller machines. | |
| NODE_PATH | ✅ | ✅ | Same as NODE_PATH in Node.js, but only relative folders are allowed. Can be handy for emulating a monorepo setup by setting NODE_PATH=src . |
npm start doesn't detect changes When you save a file while npm start is running, the browser should refresh with the updated code.
If this doesn't happen, try one of the following workarounds:
index.js and you're referencing it by the folder name, you need to restart the watcher due to a Webpack bug..env file in your project directory if it doesn't exist, and add CHOKIDAR_USEPOLLING=true to it. This ensures that the next time you run npm start , the watcher uses the polling mode, as necessary inside a VM.If none of these solutions help please leave a comment in this thread.
npm test hangs or crashes on macOS Sierra If you run npm test and the console gets stuck after printing react-scripts test to the console there might be a problem with your Watchman installation as described in facebook/create-react-app#713.
We recommend deleting node_modules in your project and running npm install (or yarn if you use it) first. If it doesn't help, you can try one of the numerous workarounds mentioned in these issues:
It is reported that installing Watchman 4.7.0 or newer fixes the issue. If you use Homebrew, you can run these commands to update it:
watchman shutdown-server
brew update
brew reinstall watchman
You can find other installation methods on the Watchman documentation page.
If this still doesn't help, try running launchctl unload -F ~/Library/LaunchAgents/com.github.facebook.watchman.plist .
There are also reports that uninstalling Watchman fixes the issue. So if nothing else helps, remove it from your system and try again.
npm run build exits too early It is reported that npm run build can fail on machines with limited memory and no swap space, which is common in cloud environments. Even with small projects this command can increase RAM usage in your system by hundreds of megabytes, so if you have less than 1 GB of available memory your build is likely to fail with the following message:
The build failed because the process exited too early. This probably means the system ran out of memory or someone called
kill -9on the process.
If you are completely sure that you didn't terminate the process, consider adding some swap space to the machine you're building on, or build the project locally.
npm run build fails on HerokuThis may be a problem with case sensitive filenames. Please refer to this section.
If you use a Moment.js, you might notice that only the English locale is available by default. This is because the locale files are large, and you probably only need a subset of all the locales provided by Moment.js.
To add a specific Moment.js locale to your bundle, you need to import it explicitly.
Misalnya:
import moment from 'moment' ;
import 'moment/locale/fr' ; If you are importing multiple locales this way, you can later switch between them by calling moment.locale() with the locale name:
import moment from 'moment' ;
import 'moment/locale/fr' ;
import 'moment/locale/es' ;
// ...
moment . locale ( 'fr' ) ;This will only work for locales that have been explicitly imported before.
npm run build fails to minify Before [email protected] , this problem was caused by third party node_modules using modern JavaScript features because the minifier couldn't handle them during the build. This has been solved by compiling standard modern JavaScript features inside node_modules in [email protected] and higher.
If you're seeing this error, you're likely using an old version of react-scripts . You can either fix it by avoiding a dependency that uses modern syntax, or by upgrading to react-scripts@>=2.0.0 and following the migration instructions in the changelog.
Ejecting lets you customize anything, but from that point on you have to maintain the configuration and scripts yourself. This can be daunting if you have many similar projects. In such cases instead of ejecting we recommend to fork react-scripts and any other packages you need. This article dives into how to do it in depth. You can find more discussion in this issue.
If you have ideas for more “How To” recipes that should be on this page, let us know or contribute some!
