Function setupWorker

src/browser/setup-worker.ts:33–120

(...handlers: Array<AnyHandler>)

 * @see {@link https://mswjs.io/docs/api/setup-worker `setupWorker()` API reference}
 */
export function setupWorker(...handlers: Array<AnyHandler>): SetupWorker {
  invariant(
    !isNodeProcess(),
    devUtils.formatMessage(
      'Failed to execute `setupWorker` in a non-browser environment',
    ),
  )

  const network = defineNetwork<
    Array<ServiceWorkerSource | FallbackHttpSource | InterceptorSource>
  >({
    sources: [],
    handlers,
  })

  return {
    async start(options) {
      if (options?.waitUntilReady != null) {
        devUtils.warn(
          `The "waitUntilReady" option has been deprecated. Please remove it from this "worker.start()" call. Follow the recommended Browser integration (https://mswjs.io/docs/integrations/browser) to eliminate any race conditions between the Service Worker registration and any requests made by your application on initial render.`,
        )
      }

      /**
       * @todo @fixme
       * This is kept for backward-compatibility reasons. We don't really need this check anymore.
       */
      if (network.readyState === NetworkReadyState.ENABLED) {
        devUtils.warn(
          'Found a redundant "worker.start()" call. Note that starting the worker while mocking is already enabled will have no effect. Consider removing this "worker.start()" call.',
        )
        return
      }

      const httpSource = supportsServiceWorker()
        ? await ServiceWorkerSource.from({
            serviceWorker: {
              url:
                options?.serviceWorker?.url?.toString() || DEFAULT_WORKER_URL,
              options: options?.serviceWorker?.options,
            },
            findWorker: options?.findWorker,
            quiet: options?.quiet,
          })
        : new FallbackHttpSource({
            quiet: options?.quiet,
          })

      network.configure({
        sources: [
          httpSource,
          new InterceptorSource({
            interceptors: [new WebSocketInterceptor() as any],
          }),
        ],
        onUnhandledFrame: fromLegacyOnUnhandledRequest(() => {
          return options?.onUnhandledRequest || 'warn'
        }),