Node.js path Module
Node.js built-in modulesNode.js'spathThe module is a built-in core module, specifically designed to handle file and directory paths.
path provides a series of practical methods that allow you to safely and efficiently manipulate file paths in different operating system environments.
Why do you need the path module?
Different operating systems use different path separators:
- Windows uses backslashes
\ - Unix/Linux/macOS use forward slashes
/
pathThe module automatically handles these differences, allowing your code to work properly on different platforms.
Basic usage of the path module
Importing the path module
const path = require('path');
Common methods
1. path.join([...paths]) - Join paths
Example
const fullPath = path.join('/user', 'documents', 'file.txt');
console.log(fullPath);
// On Unix, outputs: /user/documents/file.txt
// On Windows, outputs: \user\documents\file.txt
console.log(fullPath);
// On Unix, outputs: /user/documents/file.txt
// On Windows, outputs: \user\documents\file.txt
2. path.resolve([...paths]) - Resolve an absolute path
Example
const absolutePath = path.resolve('src', 'app.js');
console.log(absolutePath);
// Outputs the absolute path in the current working directory, e.g.: /home/user/project/src/app.js
console.log(absolutePath);
// Outputs the absolute path in the current working directory, e.g.: /home/user/project/src/app.js
3. path.basename(path[, ext]) - Get the file name
Example
console.log(path.basename('/user/docs/file.txt')); // file.txt
console.log(path.basename('/user/docs/file.txt', '.txt')); // file
console.log(path.basename('/user/docs/file.txt', '.txt')); // file
4. path.dirname(path) - Get the directory name
Example
console.log(path.dirname('/user/docs/file.txt')); // /user/docs
5. path.extname(path) - Get the file extension
Example
console.log(path.extname('index.html')); // .html
console.log(path.extname('file')); // Empty string
console.log(path.extname('file')); // Empty string
Cross-platform path handling
Path separators
path.sep- Platform-specific path separatorconsole.log(path.sep); // Windows 输出 '\', Unix 输出 '/'
path.delimiter- Platform-specific path separator (used in the PATH environment variable)console.log(path.delimiter); // Windows 输出 ';', Unix 输出 ':'
Path normalization
Usingpath.normalize(path)can normalize paths, handling redundant.、..and separators:
Example
console.log(path.normalize('/user//docs/../file.txt')); // /user/file.txt
Path parsing and format conversion
path.parse(path) - Parse a path into an object
Example
const pathObj = path.parse('/user/docs/file.txt');
console.log(pathObj);
/*
{
root: '/',
dir: '/user/docs',
base: 'file.txt',
ext: '.txt',
name: 'file'
}
*/
console.log(pathObj);
/*
{
root: '/',
dir: '/user/docs',
base: 'file.txt',
ext: '.txt',
name: 'file'
}
*/
path.format(pathObject) - Build a path from an object
Example
const pathStr = path.format({
dir: '/user/docs',
name: 'file',
ext: '.txt'
});
console.log(pathStr); // /user/docs/file.txt
dir: '/user/docs',
name: 'file',
ext: '.txt'
});
console.log(pathStr); // /user/docs/file.txt
Practical application examples
Example 1: Building cross-platform file paths
Example
const configPath = path.join(__dirname, 'config', 'settings.json');
console.log(configPath);
console.log(configPath);
Example 2: Handling user-uploaded files
Example
function saveUploadedFile(uploadDir, originalName) {
const ext = path.extname(originalName);
const baseName = path.basename(originalName, ext);
const timestamp = Date.now();
const newFileName = `${baseName}_${timestamp}${ext}`;
return path.join(uploadDir, newFileName);
}
const ext = path.extname(originalName);
const baseName = path.basename(originalName, ext);
const timestamp = Date.now();
const newFileName = `${baseName}_${timestamp}${ext}`;
return path.join(uploadDir, newFileName);
}
Example 3: Checking file extensions
Example
function isImageFile(filename) {
const ext = path.extname(filename).toLowerCase();
return ['.jpg', '.jpeg', '.png', '.gif'].includes(ext);
}
const ext = path.extname(filename).toLowerCase();
return ['.jpg', '.jpeg', '.png', '.gif'].includes(ext);
}
Methods and properties
The methods and properties of the path module are as follows:
| Method | Description | Example |
|---|---|---|
path.basename(path[, ext]) | Returns the last part of the path (file name). The optional parameterextis used to remove the file extension. | path.basename('/foo/bar/baz.txt'); // 输出: 'baz.txt' |
path.dirname(path) | Returns the directory part of the path. | path.dirname('/foo/bar/baz.txt'); // 输出: '/foo/bar' |
path.extname(path) | Returns the file extension of the path. | path.extname('/foo/bar/baz.txt'); // 输出: '.txt' |
path.join([...paths]) | Joins multiple paths into one path, automatically handling path separators. | path.join('/foo', 'bar', 'baz/asdf', 'quux', '..'); // 输出: '/foo/bar/baz/asdf' |
path.resolve([...paths]) | Resolves a sequence of paths into an absolute path, processing each path segment from right to left until an absolute path is constructed. | path.resolve('/foo/bar', './baz'); // 输出: '/foo/bar/baz' |
path.normalize(path) | Normalizes the path, removing redundant.and.., and replaces path separators according to the current operating system. | path.normalize('/foo/bar//baz/asdf/quux/..'); // 输出: '/foo/bar/baz/asdf' |
path.isAbsolute(path) | Checks whether the path is an absolute path. | path.isAbsolute('/foo/bar'); // 输出: true |
path.relative(from, to) | Returns fromfromthe path totothe relative path of the path. | path.relative('/foo/bar/baz', '/foo/bar/qux'); // 输出: '../qux' |
path.parse(path) | properties.root、dir、base、extandnameFormats the path object into a path string, which is | path.parse('/home/user/dir/file.txt');the opposite.{ root: '/', dir: '/home/user/dir', base: 'file.txt', ...} |
path.format(pathObject) | Provides the path separator of the current operating system (POSIX ispath.parse, Windows is | path.format({ root: '/', dir: '/home/user/dir', base: 'file.txt' }); // 输出: '/home/user/dir/file.txt' |
path.sep | Provides the path delimiter (the separator between paths in environment variables), POSIX is'/', Windows is'\'）。 | console.log(path.sep); // 输出: '\' (Windows) 或 '/' (POSIX) |
path.delimiter | Example:Example;。 | console.log(path.delimiter); // 输出: ';' (Windows) 或 ':' (POSIX) |
Example
Create a main.js file, the code is as follows:
Example
const path = require('path');
// Get the file name
console.log('File name:', path.basename('/foo/bar/baz.txt')); // Outputs: 'baz.txt'
// Get the directory name
console.log('Directory name:', path.dirname('/foo/bar/baz.txt')); // Outputs: '/foo/bar'
// Get the extension
console.log('Extension:', path.extname('/foo/bar/baz.txt')); // Outputs: '.txt'
// Join paths
console.log('Joined path:', path.join('/foo', 'bar', 'baz/asdf', 'quux', '..')); // Outputs: '/foo/bar/baz/asdf'
// Resolve absolute path
console.log('Absolute path:', path.resolve('/foo/bar', './baz')); // Outputs: '/foo/bar/baz'
// Normalize path
console.log('Normalized path:', path.normalize('/foo/bar//baz/asdf/quux/..')); // Outputs: '/foo/bar/baz/asdf'
// Determine whether it is an absolute path
console.log('Is absolute path:', path.isAbsolute('/foo/bar')); // Outputs: true
// Relative path
console.log('Relative path:', path.relative('/foo/bar/baz', '/foo/bar/qux')); // Outputs: '../qux'
// Parse path into object
const parsedPath = path.parse('/home/user/dir/file.txt');
console.log('Parsed path object:', parsedPath);
// Outputs: { root: '/', dir: '/home/user/dir', base: 'file.txt', ext: '.txt', name: 'file' }
// Format object as path
const formattedPath = path.format(parsedPath);
console.log('Formatted path:', formattedPath); // Outputs: '/home/user/dir/file.txt'
// Get the file name
console.log('File name:', path.basename('/foo/bar/baz.txt')); // Outputs: 'baz.txt'
// Get the directory name
console.log('Directory name:', path.dirname('/foo/bar/baz.txt')); // Outputs: '/foo/bar'
// Get the extension
console.log('Extension:', path.extname('/foo/bar/baz.txt')); // Outputs: '.txt'
// Join paths
console.log('Joined path:', path.join('/foo', 'bar', 'baz/asdf', 'quux', '..')); // Outputs: '/foo/bar/baz/asdf'
// Resolve absolute path
console.log('Absolute path:', path.resolve('/foo/bar', './baz')); // Outputs: '/foo/bar/baz'
// Normalize path
console.log('Normalized path:', path.normalize('/foo/bar//baz/asdf/quux/..')); // Outputs: '/foo/bar/baz/asdf'
// Determine whether it is an absolute path
console.log('Is absolute path:', path.isAbsolute('/foo/bar')); // Outputs: true
// Relative path
console.log('Relative path:', path.relative('/foo/bar/baz', '/foo/bar/qux')); // Outputs: '../qux'
// Parse path into object
const parsedPath = path.parse('/home/user/dir/file.txt');
console.log('Parsed path object:', parsedPath);
// Outputs: { root: '/', dir: '/home/user/dir', base: 'file.txt', ext: '.txt', name: 'file' }
// Format object as path
const formattedPath = path.format(parsedPath);
console.log('Formatted path:', formattedPath); // Outputs: '/home/user/dir/file.txt'