Set assumptions in order to produce smaller output.

Decorator plugin

Replace global variables or property accessors with the provided values.

Examples

• Replace the global variable IS_PROD with true

export default defineConfig({ transform: { define: { IS_PROD: 'true' } } })
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Result:

// Input
if (IS_PROD) {
  console.log('Production mode')
}

// After bundling
if (true) {
  console.log('Production mode')
}
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• Replace the property accessor process.env.NODE_ENV with 'production'

export default defineConfig({ transform: { define: { 'process.env.NODE_ENV': "'production'" } } })
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Result:

// Input
if (process.env.NODE_ENV === 'production') {
 console.log('Production mode')
}

// After bundling
if ('production' === 'production') {
console.log('Production mode')
}

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Remove labeled statements with these label names.

Labeled statements are JavaScript statements prefixed with a label identifier. This option allows you to strip specific labeled statements from the output, which is useful for removing debug-only code in production builds.

Example

export default defineConfig({ transform: { dropLabels: ['DEBUG', 'DEV'] } })
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Result:

// Input
DEBUG: console.log('Debug info');
DEV: {
  console.log('Development mode');
}
console.log('Production code');

// After bundling
console.log('Production code');
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Behaviour for runtime helpers.

Inject import statements on demand.

The API is aligned with @rollup/plugin-inject.

Supported patterns

{
  // import { Promise } from 'es6-promise'
  Promise: ['es6-promise', 'Promise'],

  // import { Promise as P } from 'es6-promise'
  P: ['es6-promise', 'Promise'],

  // import $ from 'jquery'
  $: 'jquery',

  // import * as fs from 'node:fs'
  fs: ['node:fs', '*'],

  // Inject shims for property access pattern
  'Object.assign': path.resolve( 'src/helpers/object-assign.js' ),
}
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Third-party plugins to use.

Sets the target environment for the generated JavaScript.

The lowest target is es2015.

Example:

• 'es2015'
• ['es2020', 'chrome58', 'edge16', 'firefox57', 'node12', 'safari11']

Configure how TypeScript is transformed.