Path related APIs

+-- myProject
|	+-- node_modules
|		+-- lodash
|	+-- src
|   	+-- cwd.js
|		+-- dirname.js
|		+-- require.js

switch current working directory into myProject

pwd // '/Users/michaelzheng/Desktop/myProject'

process.cwd

The process.cwd() method returns the current working directory of the node.js process. i.e. the directory from which you invoked the node command.

relative to the process

#!/usr/bin/env node

// cwd.js
process.cwd(); 
// Returns '/Users/michaelzheng/Desktop/myProject'

Use case: fetch project config file which is usually set based on project root. e.g. webpack config file.

__dirname

returns the directory name of the directory containing the JavaScript source code file.

relative to the source code �

#!/usr/bin/env node

// dirname.js
__dirname; 
// Returns '/Users/michaelzheng/Desktop/myProject/src'

Use case: get absolute path of a file

require.resolve

use(es) the internal require() machinery to look up the location of a module, but rather than loading the module, just return(s) the resolved filename.

works for module resolution

// require.js
require.resolve('lodash'); 
// Returns /Users/michaelzheng/Desktop/myProject/node_modules/lodash/lodash.js

Use case: resolve node modules which are not installed on current working directory.

path.resolve

The path.resolve() method resolves a sequence of paths or path segments into an absolute path .

always returns absolute path

path.resolve('/foo/bar', './baz');
// Returns: '/foo/bar/baz'

path.resolve('/foo/bar', '/tmp/file/');
// Returns: '/tmp/file'

path.join

The path.join() method joins all given path segments together using the platform-specific separator as a delimiter, then normalizes the resulting path.

path.join('/foo', 'bar', 'baz/asdf', 'quux', '..'); 
// Returns '/foo/bar/baz/asdf'

path.join('foo', 'bar', 'baz/asdf', 'quux', '..'); 
// Returns 'foo/bar/baz/asdf'

Notice

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