terserPlugin() — vite Function Reference

Architecture documentation for the terserPlugin() function in terser.ts from the vite codebase.

Function typescript PluginSystem LegacySupport calls 2 called by 1

Entity Profile

PluginSystem→ LegacySupport→ terserPlugin() — vite Function Reference

Dependency Diagram

graph TD
  087bc308_b1da_3dca_40fd_0cf762502823["terserPlugin()"]
  be81372e_415b_426f_d3c1_132b2d458ce6["terser.ts"]
  087bc308_b1da_3dca_40fd_0cf762502823 -->|defined in| be81372e_415b_426f_d3c1_132b2d458ce6
  8c4db194_5dfd_4391_cc9a_833655009196["resolveBuildPlugins()"]
  8c4db194_5dfd_4391_cc9a_833655009196 -->|calls| 087bc308_b1da_3dca_40fd_0cf762502823
  39ac1178_9b7e_dd67_f753_f2fb1b78e04a["loadTerserPath()"]
  087bc308_b1da_3dca_40fd_0cf762502823 -->|calls| 39ac1178_9b7e_dd67_f753_f2fb1b78e04a
  310ed049_c1b4_c917_b399_81bab290e5a2["generateCodeFrame()"]
  087bc308_b1da_3dca_40fd_0cf762502823 -->|calls| 310ed049_c1b4_c917_b399_81bab290e5a2
  style 087bc308_b1da_3dca_40fd_0cf762502823 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

packages/vite/src/node/plugins/terser.ts lines 38–139

export function terserPlugin(config: ResolvedConfig): Plugin {
  const { maxWorkers, ...terserOptions } = config.build.terserOptions

  const makeWorker = () =>
    new WorkerWithFallback(
      () =>
        async (
          terserPath: string,
          code: string,
          options: TerserMinifyOptions,
        ) => {
          const terser: typeof import('terser') = await import(terserPath)
          try {
            return (await terser.minify(code, options)) as TerserMinifyOutput
          } catch (e) {
            // convert to a plain object as additional properties of Error instances are not
            // sent back to the main thread
            throw { stack: e.stack /* stack is non-enumerable */, ...e }
          }
        },
      {
        shouldUseFake(_terserPath, _code, options) {
          return !!(
            (typeof options.mangle === 'object' &&
              (options.mangle.nth_identifier?.get ||
                (typeof options.mangle.properties === 'object' &&
                  options.mangle.properties.nth_identifier?.get))) ||
            typeof options.format?.comments === 'function' ||
            typeof options.output?.comments === 'function' ||
            options.nameCache
          )
        },
        max: maxWorkers,
      },
    )

  let worker: ReturnType<typeof makeWorker>

  return {
    name: 'vite:terser',

    applyToEnvironment(environment) {
      // We also need the plugin even if minify isn't 'terser' as we force
      // terser in plugin-legacy
      return !!environment.config.build.minify
    },

    async renderChunk(code, chunk, outputOptions) {
      // This plugin is included for any non-false value of config.build.minify,
      // so that normal chunks can use the preferred minifier, and legacy chunks
      // can use terser.
      if (
        config.build.minify !== 'terser' &&
        !this.environment.config.isOutputOptionsForLegacyChunks?.(outputOptions)
      ) {
        return null
      }

      // Lazy load worker.
      worker ||= makeWorker()

      const terserPath = pathToFileURL(loadTerserPath(config.root)).href
      try {
        const res = await worker.run(terserPath, code, {
          safari10: true,
          ...terserOptions,
          format: {
            ...terserOptions.format,
            // For ES lib mode, preserve comments to keep pure annotations for tree-shaking
            preserve_annotations:
              config.build.lib && outputOptions.format === 'es'
                ? true
                : terserOptions.format?.preserve_annotations,
          },
          sourceMap: !!outputOptions.sourcemap,
          module: outputOptions.format.startsWith('es'),
          toplevel: outputOptions.format === 'cjs',
        })
        return {
          code: res.code!,
          map: res.map as any,