Synchronous and asynchronous implementation of file system in Node.js

The content of this article is about the implementation of synchronization and asynchronousness of the file system in Node.js. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

1. Synchronous and asynchronous

All methods have asynchronous and synchronous forms;

The last parameter of an asynchronous method is a callback function. The parameters passed to the callback function depend on the specific method, but the first parameter of the callback function is reserved for exceptions. If the operation completes successfully, the first parameter will be null or undefined.

Example: Directory fs/fs-1.js:

//导入fs模块
const fs = require('fs');
// 同步和异步
//  ============例子1：实现重命名文件 rename()==========
// 异步方法
fs.rename('./text.txt', 'hello.txt', function (err) {
    if (err) throw err;
    console.log('异步重命名成功');
})
// 同步方法
fs.renameSync('./hello.txt','zhang.txt');
console.log('同步重命名成功');


 例子2：新建目录  mkdir()，并修改目录名称==========
fs.mkdir('test',function (err) {
    if(err) throw  err;
    // 重命名目录名称
    fs.rename('./test','./new',function (err) {
        if(err) throw err;
        console.log("目录创建并重命名成功");
    })
});

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