Node.js fs.readdir()方法
fs.readdir()方法用于异步读取给定目录的内容。此方法的回调返回目录中所有文件名的数组。options 参数可用于更改从方法返回文件的格式。
语法:
fs.readdir( path, options, callback )
参数:该方法接受三个参数，如上所述，如下所述:
- Path: The directory path where the content to be read is saved. It can be a string, a buffer or a web address.
- Option: is an object that can be used to specify optional parameters that affect the method. It has two optional parameters:
- Encoding: It is a string value that specifies which encoding is used for the file name of the callback parameter. The default value is utf8.
- with file type: is a Boolean value that specifies whether the file is returned as a file system. Direct object. The default value is false.
- Callback: is a function that will be called when the method is executed.
- err: If the operation fails, this error will be thrown.
- File: is an array of String, Buffer or fs. A directory object that contains files in the directory.
下面的例子说明了 Node.js 中的 fs.readdir()方法:
示例 1: 本示例使用 fs.readdir()方法返回目录中的文件名或文件对象。
// Node.js program to demonstrate the
// fs.readdir() method
// Import the filesystem module
const fs = require('fs');
// Function to get current filenames
// in directory
fs.readdir(__dirname, (err, files) => {
if (err)
console.log(err);
else {
console.log("\nCurrent directory filenames:");
files.forEach(file => {
console.log(file);
})
}
})
// Function to get current filenames
// in directory with "withFileTypes"
// set to "true"
fs.readdir(__dirname,
{ withFileTypes: true },
(err, files) => {
console.log("\nCurrent directory files:");
if (err)
console.log(err);
else {
files.forEach(file => {
console.log(file);
})
}
})
输出:
Current directory filenames:
index.js
package.json
text_file_a.txt
text_file_b.txt
Current directory files:
Dirent { name: 'index.js', [Symbol(type)]: 1 }
Dirent { name: 'package.json', [Symbol(type)]: 1 }
Dirent { name: 'text_file_a.txt', [Symbol(type)]: 1 }
Dirent { name: 'text_file_b.txt', [Symbol(type)]: 1 }
示例 2: 本示例使用 fs.readdir()方法仅返回带有“.”的文件名。txt "扩展名。
// Node.js program to demonstrate the
// fs.readdir() method
// Import the filesystem module
const fs = require('fs');
const path = require('path');
// Function to get current filenames
// in directory with specific extension
fs.readdir(__dirname, (err, files) => {
if (err)
console.log(err);
else {
console.log("\Filenames with the .txt extension:");
files.forEach(file => {
if (path.extname(file) == ".txt")
console.log(file);
})
}
})
输出:
Filenames with the .txt extension:
text_file_a.txt
text_file_b.txt
参考:https://nodejs . org/API/fs . html # fs _ fs _ readdir _ path _ options _ callback
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