NormalModuleReplacementPlugin

The NormalModuleReplacementPlugin allows you to replace resources that match resourceRegExp with newResource. If newResource is relative, it is resolved relative to the previous resource. If newResource is a function, it is expected to overwrite the request attribute of the supplied resource.

This can be useful for allowing different behaviour between builds.

new webpack.NormalModuleReplacementPlugin(resourceRegExp, newResource);

Note that the resourceRegExp is tested against the request you write in your code, not the resolved resource. For instance, './sum' will be used to test instead of './sum.js' when you have code import sum from './sum'.

Also please note that when using Windows, you have to accommodate the different folder separator symbol. E.g. /src\/environments\/environment\.ts/ won't work on Windows, you have to use /src[\\/]environments[\\/]environment\.ts/, instead.

Basic Example

Replace a specific module when building for a development environment.

Say you have a configuration file some/path/config.development.module.js and a special version for production in some/path/config.production.module.js

Add the following plugin when building for production:

new webpack.NormalModuleReplacementPlugin(   /some\/path\/config\.development\.js/,   './config.production.js' );

Advanced Example

Conditional build depending on an specified environment.

Say you want a configuration with specific values for different build targets.

module.exports = function (env) {   var appTarget = env.APP_TARGET || 'VERSION_A';   return {     plugins: [       new webpack.NormalModuleReplacementPlugin(/-APP_TARGET$/, function (         resource       ) {         resource.request = resource.request.replace(           /-APP_TARGET/,           `-${appTarget}`         );          if (resource.createData) {           resource.createData.request = resource.request;         }       }),     ],   }; };

Create the two configuration files:

app/config-VERSION_A.js

export default {   title: 'I am version A', };

app/config-VERSION_B.js

export default {   title: 'I am version B', };

Then import that configuration using the keyword you're looking for in the regexp:

import config from 'app/config-APP_TARGET'; console.log(config.title);

And now you get the right configuration imported depending on which target you're building for:

npx webpack --env APP_TARGET=VERSION_A => 'I am version A'  npx webpack --env APP_TARGET=VERSION_B => 'I am version B'