Module Replace Webpack Plugin

A webpack plugin to replace any imported file/module before build.

There are times when you would want to monkey patch a third party library, for instance lodash. Creating a forked version or putting in a PR are both sometimes either too cumbersome or not practically possible. Another possible way is to patch it and ask all devs to start referencing to lodash as

const lodash = require('./patchedLodash')

OR

import lodash from './patchedLodash'

Although this can get the job done, a more elegant way could be to let the devs import lodash the usual way, but include a plugin in the webpack build process to replace all lodash imports with your patched version.

So in other words, webpack will change all occurrences of

const lodash = require('lodash')

to

const lodash = require('./patchedLodash')

OR

import lodash from 'lodash'

to

import lodash from './patchedLodash'

when building your application.

Version

This plugin is only tested on webpack version 3.x.

Support for other webpack versions could be taken up in the future.

Installation

npm i module-replace-webpack-plugin --save-dev

Usage

const ModuleReplaceWebpackPlugin = require('module-replace-webpack-plugin');
 
// webpack config
{
  plugins: [
    new ModuleReplaceWebpackPlugin({options})
  ]
}

Example Webpack Config

const ModuleReplaceWebpackPlugin = require('module-replace-webpack-plugin');
const path = require('path');
 
module.exports = {
  entry: './index.js',
  output: {
    filename: 'bundle.js',
    path: path.resolve(__dirname, 'dist')
  },
  plugins: [
    new ModuleReplaceWebpackPlugin({
      modules: [{
        test: /lodash/,
        replace: './src/patchedLodash.js'
      }],
      exclude: [/patchedLodash.js$/]
    })
  ]
}
 

Options

modules (Array of objects) (required)

Contains config that will be used to replace import statements during build process.

example

module: [{
  test: /lodash/,
  require: './src/patchedLodash.js'
}],

NOTE:

• This options is an array and is a required.

test (regex)

Regex that will be used to test the import statements.

for example test: /lodash/, will match import { map } from 'lodash' and import lodash from 'lodash'

NOTE:

• If multiple objects are provided that match the same module, the config for the first one that matches will be used.

replace (string) (required)

Contains the path to the file that will be used to replace the module with.

example require: './src/patchedLodash.js'

NOTE:

• This path should be provided from the root directory.
• file extension is mandatory
• if resolve options is provided in the webpack config, this will first find the file in root and then try to find the file in paths defined under resolve.

exclude (Array of regex)

If the file that is being build has an import statement that matches the test regex, that file can be forced to not replace that import statement by including its path in the exclude setting.

In other words, mention regex for files for which you dont want this plugin to run.