webpack-test-utils 
Utility functions to test Webpack loaders/plugins
Features
- In-memory builds Uses an in-memory file-system for faster builds that don't pollute your disk
- TypeScript support Get type hints and develop with confidence
- Sensible defaults Builds in production-mode by default with minification disabled
- Webpack 4 & 5 support Both versions are supported
🚀 Install
npm i -D webpack-test-utils👨🏫 Usage
Build
import { build } from 'webpack-test-utils'
test('build', async () => {
// Create in-memory file-system
const volume = {
'/src/index.js': 'export default "12345"'
}
// Run Webpack build
const built = await build(volume)
// Verify successful build
expect(built.stats.hasErrors()).toBe(false)
expect(built.stats.hasWarnings()).toBe(false)
// Run the code to verify result
expect(built.require('/dist/index.js')).toBe('12345')
})Watch
import { watch } from 'webpack-test-utils'
test('watch', async () => {
// Create in-memory file-system
const volume = {
'/src/index.js': 'export default "12345"'
}
// Create Webpack watcher
const watching = watch(volume)
// Create build
let stats = await watching.build()
// Verify result
expect(stats.hasWarnings()).toBe(false)
expect(watching.require('/dist')).toBe('12345')
// Update source code
watching.fs.writeFileSync('/src/index.js', 'export default "54321"')
// Rebuild
stats = await watching.build()
expect(stats.hasWarnings()).toBe(false)
// Delete cache and re-require to validate changed result
delete watching.require.cache[watching.require.resolve('/dist')]
expect(watching.require('/dist')).toBe('54321')
// Close watcher
await watching.close()
})⚙️ API
build(volume, configHook)
Returns: Promise<WebpackStats>
Run a single Webpack build.
volume
Type: { [filePath: string]: string }
Required
An object where the key is the absolute path, and the value is the content of the path.
configurationHook
Type: (config: WebpackConfiguration) => void
A function that receives the Webpack configuration object for configuration before running the build.
watch(volume, configHook)
Returns: Promise<WebpackStats>
Run a single Webpack build.
volume
Type: { [filePath: string]: string }
Required
An object where the key is the absolute path, and the value is the content of the path.
configurationHook
Type: (config: WebpackConfiguration) => void
A function that receives the Webpack configuration object for configuration before running the build.