path-alias

This module allows you to use path aliases in your NodeJS modules and client-side (in browser).

The problem

Probably In a big project you will have something like this:

require('../../../packages/user/models/role') - relative paths

Even if you use a root path detector:

var pathFromRoot = require('some-module-to-detect-root')
require(pathFromRoot('app/packages/user/models/role'))

It is a mess! Imagine that you need to rename/move some file or directory, you need to change each of these paths to point to the new location.

How to solve it?

Use path-alias!

var pathAlias = require('path-alias');
 
//setup alias:
pathAlias.setAlias('user', 'app/packages/user');
 
//require module:
var role = pathAlias('@user/models/role');

You can also use variables in any parts:

pathAlias.setAlias('c', 'client-side', false);
 
// will require file: app/packages/user/models/some.client-side.js
var clientModel = pathAlias('@user/models/some.@c');

Also you can use this module to require root-related files:

// will require {PROJECT_ROOT}/app/myModule
var someModule = pathAlias('app/myModule');

Methods

Calling with argument - will resolve path, require it and return a module.

var pathAlias = require('path-alias');
 
//with aliases
var myModel = pathAlias('@user/models/myModel');
 
//just add root prefix
var anotherModel = pathAlias('app/modules/myModule');

getRoot()/setRoot()

var pathAlias = require('path-alias');
//root path will be detected
console.log(pathAlias.getRoot());

The directory with package.json is considered a project's root directory.

You can also set custom root-path:

pathAlias.setRoot('/you/custom/path')

setAlias/setAliases/getAliases

pathAlias.setAlias('alias', 'path or suffix', resolve);

resolve - should path be resolved or not. True by default.

How does it work?

• './path/' - path, related to caller location will be transformed to absolute
• 'some/path' - root path will be added to non absolute path

If you want to add file suffix you will not want to resolve this alias:

pathAlias.setAlias('c', 'client-suffix', false);

setAliases/getAliases

pathAlias.setAliases({
    'user' : 'app/packages/user'
});

resolve

Resolve path and return it:

var path = pathAlias.resolve('@user/models/myModel');

exportAliasesForClientSide

It needs to export aliases for client-side module.

Using client-side

1. Add pathAlias loader to your webpack config. It replaces all pathAlias('@some/path.@c') entries to require('/resolved/some/path.client'). Path will be resolved before passing it to require().

const aliasLoader = {
    loader: path.resolve('node_modules/path-alias/webpack/loader.js'),
    options: {
        test: (filePath) => {
            //some custom logick to include/exclude files from loader.
        },
    }
}
 

1. In your client side, if you want to use pathAlias for dynamic require, you need to pass require.context to pathAlias:

const contextRequire = require.context('./app', true, /widgets\/[^\/]+\.client\.(js|coffee)$/i);
const pathAlias = require('path-alias');
 
pathAlias.setAliases({
    'c': 'client',
    'widgets': './widgets'
});
 
pathAlias.setRequireCallback((filePath, resolved) => {
    if (!/\.(js|coffee)$/i.test(resolved)) {
        let foundExt = null;
        let found = contextRequire.keys().find((item) => {
            if (`${resolved}.js` == item) {
                foundExt = 'js';
                return true;
            }
 
            if (`${resolved}.coffee` == item) {
                foundExt = 'coffee';
                return true;
            }
        });
 
        if (found)
            resolved += `.${foundExt}`;
    }
 
    return contextRequire(resolved);
});