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Source.define property

The define options is used to define some values or expressions at compile time.

Signature:

define?: Rspack.DefinePluginOptions;

Default Value

undefined

Remarks

If the value provided is a string, it will be utilized as a code fragment.
If the value provided is an object, all its keys will be defined in the same manner.
If the value isn't a string, it will be stringified, with functions included.
Notably, if a typeof prefix is attached to the key, it will be exclusively defined for typeof calls."

Example 1

Using define for environment variables.

import { defineConfig } from '@lynx-js/rspeedy'
export default defineConfig({
  source: {
    define: {
      BUILD_VERSION: JSON.stringify(process.env.BUILD_VERSION ?? 'unknown_version'),
      'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV),
    },
  },
})

Expressions will be replaced with the corresponding code fragments:

const version = BUILD_VERSION;
if (process.env.NODE_ENV === 'development') {}

// ⬇️ Turn into being...
const version = "unknown_version";
if ("development" === 'development') {}

Example 2

Using define for typeof.

import { defineConfig } from '@lynx-js/rspeedy'
export default defineConfig({
  source: {
    define: {
      'typeof window': JSON.stringify("undefined"),
    },
  },
})

The typeof expressions will be replaced with the corresponding code fragments:

if (typeof window !== 'undefined') {}

// ⬇️ Turn into being...
if ("undefined" !== 'undefined') {}

Example 3

Using define with objects.

import { defineConfig } from '@lynx-js/rspeedy'
export default defineConfig({
  source: {
    define: {
      'import.meta': {
        foo: JSON.stringify('foo'),
        bar: { baz: 0 },
      },
    },
  },
})

Expressions will be replaced with the corresponding code fragments:

console.log(import.meta)

// ⬇️ Turn into being...
console.log({ foo: "foo", bar: { baz: 0 } })

#Source.define property

#Default Value

#Remarks

#Example 1