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Learn about using node (I)
2021-08-27 08:53:22 【Front end worker】
This is my participation 8 The fourth of the yuegengwen challenge 23 God , Check out the activity details :8 Yuegengwen challenge
brief introduction
Node.js It's based on Chrome V8 Engine JavaScript Runtime , You can set up a server to run JavaScript Applications , You can also write some scripts yourself .
install
We can log in node.js Official website installation LTS edition ( Stable version ), After the installation, we check whether the installation is successful :
Console execution npm -v and node -v The version number indicates that the installation is successful
Use node Make one HTTP The server
- introduce required modular
var http = require("http");
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- createServer() Method to create a server
var http = require('http');
http.createServer(function (request, response) {
// send out HTTP Head
// HTTP The status value : 200 : OK
// Content type : text/plain
response.writeHead(200, {'Content-Type': 'text/plain'});
// Send response data "Hello World"
response.end('Hello World\n');
}).listen(8888);
// The terminal prints the following information
console.log('Server running at http://127.0.0.1:8888/')
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So our web The server is created , Can be accessed by 127.0.0.1:8888 To visit your own web.
Use node Develop your own tool scripts
Let's implement a requirement : Need to put css In the file px The unit is converted into rem Company
- introduce fs,path modular
var fs = require("fs");
var path = require('path');
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fs and path Two modules are convenient for us to operate folders and files
- Traverse the target folder
Prepare a dish containing css File folder , Traverse the target folder , Get its file list :
var fs = require("fs");
var path = require('path'); // Resolve the folders that need to be traversed
var filePath = path.resolve('./css');
fileDisplay(filePath);
function isDir(path){ // Is it a directory
return fs.statSync(path).isDirectory();
}
function fileDisplay(filePath) {
// Read the file according to the file path , Return to file list
fs.readdir(filePath, function(err, files) {
if(err) {
console.warn(err, 111)
} else {
// Traverse the read file list
files.forEach(function(filename) {
var s = path.join(filePath, filename)
if (isDir(s)) { // Catalog
fileDisplay(s)
} else { // file
handleFile(s)
}
});
}
});
}
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- Prepare regular expression rules corresponding to requirements , Process the obtained file list , Overwrite the original file after processing :
function handleFile(path) {
fs.readFile(path, 'utf8', function(err, data) {
if(err) {
console.warn(err)
} else {
//css Partial capture
if(path.indexOf(".css") != -1) {
replaceCss(data, path)
}
}
});
}
function replaceCss(fileContent, fileName) {
var str = fileContent;
str = str.replace(/\d*.?\d+px/g, function(a) {
console.log('rem', a)
return parseFloat(a) + 'rem';
});
fs.writeFileSync(fileName, str);
}
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With such a simple scripting tool, we have completed , You can use your imagination to write some scripts to deal with some daily development work and reduce cumbersome repeated operations .
copyright notice
author[Front end worker],Please bring the original link to reprint, thank you.
https://en.qdmana.com/2021/08/20210827085319320I.html
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