Function buildOutputOptions

packages/vite/src/node/build.ts:689–792

(output: OutputOptions = {})

  }

  const buildOutputOptions = (output: OutputOptions = {}): OutputOptions => {
    // @ts-expect-error See https://github.com/vitejs/vite/issues/5812#issuecomment-984345618
    if (output.output) {
      logger.warn(
        `You've set "rolldownOptions.output.output" in your config. ` +
          `This is deprecated and will override all Vite.js default output options. ` +
          `Please use "rolldownOptions.output" instead.`,
      )
    }
    if (output.file) {
      throw new Error(
        `Vite does not support "rolldownOptions.output.file". ` +
          `Please use "rolldownOptions.output.dir" and "rolldownOptions.output.entryFileNames" instead.`,
      )
    }
    if (output.sourcemap) {
      logger.warnOnce(
        colors.yellow(
          `Vite does not support "rolldownOptions.output.sourcemap". ` +
            `Please use "build.sourcemap" instead.`,
        ),
      )
    }

    const format = output.format || 'es'
    const jsExt =
      (ssr && !isSsrTargetWebworkerEnvironment) || libOptions
        ? resolveOutputJsExtension(
            format,
            findNearestPackageData(root, packageCache)?.data.type,
          )
        : 'js'
    return {
      dir: outDir,
      // Default format is 'es' for regular and for SSR builds
      format,
      exports: 'auto',
      sourcemap: options.sourcemap,
      name: libOptions ? libOptions.name : undefined,
      // hoistTransitiveImports: libOptions ? false : undefined,
      // es2015 enables `generatedCode.symbols`
      // - #764 add `Symbol.toStringTag` when build es module into cjs chunk
      // - #1048 add `Symbol.toStringTag` for module default export
      generatedCode: {
        preset: 'es2015',
      },
      entryFileNames: ssr
        ? `[name].${jsExt}`
        : libOptions
          ? ({ name }) =>
              resolveLibFilename(
                libOptions,
                format,
                name,
                root,
                jsExt,
                packageCache,
              )