Function lazyInitializer

packages/react/src/ReactLazy.js:68–193

(payload: Payload<T>)

};

function lazyInitializer<T>(payload: Payload<T>): T {
  if (payload._status === Uninitialized) {
    if (__DEV__ && enableAsyncDebugInfo) {
      const ioInfo = payload._ioInfo;
      if (ioInfo != null) {
        class="cm">// Mark when we first kicked off the lazy request.
        class="cm">// $FlowFixMe[cannot-write]
        ioInfo.start = ioInfo.end = performance.now();
      }
    }
    const ctor = payload._result;
    const thenable = ctor();
    class="cm">// Transition to the next state.
    class="cm">// This might throw either because it's missing or throws. If so, we treat it
    class="cm">// as still uninitialized and try again next time. Which is the same as what
    class="cm">// happens if the ctor or any wrappers processing the ctor throws. This might
    class="cm">// end up fixing it if the resolution was a concurrency bug.
    thenable.then(
      moduleObject => {
        if (
          (payload: Payload<T>)._status === Pending ||
          payload._status === Uninitialized
        ) {
          class="cm">// Transition to the next state.
          const resolved: ResolvedPayload<T> = (payload: any);
          resolved._status = Resolved;
          resolved._result = moduleObject;
          if (__DEV__) {
            const ioInfo = payload._ioInfo;
            if (ioInfo != null) {
              class="cm">// Mark the end time of when we resolved.
              class="cm">// $FlowFixMe[cannot-write]
              ioInfo.end = performance.now();
            }
            class="cm">// Make the thenable introspectable
            if (thenable.status === undefined) {
              const fulfilledThenable: FulfilledThenable<{default: T, ...}> =
                (thenable: any);
              fulfilledThenable.status = class="st">'fulfilled';
              fulfilledThenable.value = moduleObject;
            }
          }
        }
      },
      error => {
        if (
          (payload: Payload<T>)._status === Pending ||
          payload._status === Uninitialized
        ) {
          class="cm">// Transition to the next state.
          const rejected: RejectedPayload = (payload: any);
          rejected._status = Rejected;
          rejected._result = error;
          if (__DEV__ && enableAsyncDebugInfo) {
            const ioInfo = payload._ioInfo;
            if (ioInfo != null) {
              class="cm">// Mark the end time of when we rejected.
              class="cm">// $FlowFixMe[cannot-write]