A brief analysis of some APIs of the path module in node

1. A first introduction to the path module.

The path module is a module officially provided by Node.js for processing paths . It provides a series of methods and attributes to meet users' needs for path processing.

2. Path module API

2.1 path.join()

path.join() method is used to splice multiple path fragments into a complete path string.

The syntax format is:

...paths(string) The sequence of path fragments is all the path series you need to splice.

It should be noted that the returned value is string

//Introduce the path module const path=require("path")
//Write the path to be spliced ​​const pathStr=path.join('/a','/b/c','../','./d','e')

console.log(pathStr)

2.2 path.basename()

Use the path.basename() method to obtain the last part of the path. This method is often used to obtain

the syntax format

• path is a required parameter, a string representing a path.
• Optional parameter, representing the file extension,
• representing the last part of the path.

const path=require("path")

const fpath='./a/b/c/index.html'

var fullname=path.basename(fpath)

console.log(fullname)
//Get the file name with the specified suffix const namepath=path.basename(fpath,'.html')

console.log(namepath)

2.3 path.extname()

path.extname() is used to obtain the file extension in the path.

The format is

• path is a required parameter, a string representing a path.

• Return: Returns the obtained extension string

const path=require("path")

const fpath='./a/b/c/d/index.html'

const ftext =path.extname(fpath)

console.log(ftext)

3. In the clock case practice,

split the provided code (one file has html, css, and js at the same time) into three files, namely index.html index.css index.js and store them in a prepared

Source code

in the file

3.1 Implementation steps

1. Create two regular expressions to match <style> and <script> tags respectively
2. Use the fs module to read the HTML file that needs to be processed
3. Customize the resolveCSS method to write the index.css style file
4. Customize the resolveJS method to write the index.js script file
5. Customize the resolveHTML method to write the index.html file

3.1.1 Step 1 - Import the required modules and create the regular expression

const path=require('path')
const fs=require('fs')

const regStyle=/<style>[sS]*</style>/

const scriptruler=/<script>[sS]*</script>/
//The file to be read fs.readFile(path.join(__dirname,'/static/index.html'),'utf-8',function(err,dateStr){
    if(err){
        return console.log("Read failed")
    }
   resolveCSS(dateStr)
   resolveHTML(dateStr)
   resolveJS(dateStr)
})

3.1.2 Custom resolveCSS resolveHTML resolveJS method

function resolveCSS(htmlStr){
    const r1=regStyle.exec(htmlStr)
    const newcss=r1[0].replace('<style>','').replace('</style>','')
    //Write the matching css into the specified index.css file fs.writeFile(path.join(__dirname,'/static/index.css'),newcss,function(err){
        if(err) return console.log("Import failed"+err.message)
        console.log("ojbk")
    })
}
function resolveJS(htmlStr){
    const r2=scriptruler.exec(htmlStr)
    const newcss=r2[0].replace('<script>','').replace('</script>','')
    //Write the matching css into the specified index.js file fs.writeFile(path.join(__dirname,'/static/index.js'),newcss,function(err){
        if(err) return console.log("Import failed"+err.message)
        console.log("ojbk")
    })
}
function resolveHTML(htmlStr){
    const newhtml=htmlStr
    .replace(regStyle,'<link rel="stylesheet" href="./index.css">')
    .replace(scriptruler,'<script src="./index.js"></script>')
    //Write the matching css into the specified index.html file fs.writeFile(path.join(__dirname,'/static/index2.html'),newhtml,function(err){
        if(err) return console.log("Import failed"+err.message)
        console.log("ojbk")
    })
}

The final result is to peel off the style in the specified file

. However, since the initial index.html contains all the code, the location where it is stored when the style is split is still the original, so the final index.html code constant