Function transformStableResult

packages/vite/src/node/utils.ts:1579–1591

(
  s: MagicString,
  id: string,
  config: ResolvedConfig,
)

 * so we can skip sourcemap generation during dev
 */
export function transformStableResult(
  s: MagicString,
  id: string,
  config: ResolvedConfig,
): TransformResult {
  return {
    code: s.toString(),
    map:
      config.command === 'build' && config.build.sourcemap
        ? s.generateMap({ hires: 'boundary', source: id })
        : null,
  }
}

type AsyncFlatten<T extends unknown[]> = T extends (infer U)[]
  ? Exclude<Awaited<U>, U[]>[]