💉👾 A Webpack loader for injecting code into modules via their dependencies
This is particularly useful for writing tests where mocking things inside your module-under-test is sometimes necessary before execution.
inject-loader was inspired by, and builds upon ideas introduced in jauco/webpack-injectable.
Use the inject loader by adding inject-loader! when you use require, this will return a function that can be passed things to inject.
By default all require statements in an injected module will be altered to be replaced with an injector, though if a replacement it not specified the default will be used.
Given some code in a module like this:
// MyStore.js
var Dispatcher = require('lib/dispatcher');
var EventEmitter = require('events').EventEmitter;
var handleAction = require('lib/handle_action');
Dispatcher.register(handleAction, 'MyStore');You can manipulate it’s dependencies when you come to write tests as follows:
// If no flags are provided when using the loader then
// all require statements will be wrapped in an injector
MyModuleInjector = require('inject-loader!MyStore')
MyModule = MyModuleInjector({
'lib/dispatcher': DispatcherMock,
'events': EventsMock,
'lib/handle_action': HandleActionMock
})There are a few examples of complete test setups for both Webpack 1 & 2 in the example folder.