Function loadHookNames

packages/react-devtools-shared/src/hookNamesCache.js:75–226

(
  element: Element,
  hooksTree: HooksTree,
  loadHookNamesFunction: LoadHookNamesFunction,
  fetchFileWithCaching: FetchFileWithCaching | null,
)

}

export function loadHookNames(
  element: Element,
  hooksTree: HooksTree,
  loadHookNamesFunction: LoadHookNamesFunction,
  fetchFileWithCaching: FetchFileWithCaching | null,
): HookNames | null {
  let record = map.get(element);

  if (__DEBUG__) {
    console.groupCollapsed('loadHookNames() record:');
    console.log(record);
    console.groupEnd();
  }

  if (!record) {
    const callbacks = new Set<(value: any) => mixed>();
    const rejectCallbacks = new Set<(reason: mixed) => mixed>();
    const thenable: Thenable<HookNames> = {
      status: 'pending',
      value: null,
      reason: null,
      then(callback: (value: any) => mixed, reject: (error: mixed) => mixed) {
        callbacks.add(callback);
        rejectCallbacks.add(reject);
      },

      // Optional property used by Timeline:
      displayName: `Loading hook names for ${element.displayName || 'Unknown'}`,
    };

    let timeoutID: $FlowFixMe | null;
    let didTimeout = false;
    let status: 'success' | 'error' | 'timeout' | 'unknown' = 'unknown';
    let resolvedHookNames: HookNames | null = null;

    const wake = () => {
      if (timeoutID) {
        clearTimeout(timeoutID);
        timeoutID = null;
      }

      // This assumes they won't throw.
      callbacks.forEach(callback => callback((thenable: any).value));
      callbacks.clear();
      rejectCallbacks.clear();
    };
    const wakeRejections = () => {
      if (timeoutID) {
        clearTimeout(timeoutID);
        timeoutID = null;
      }
      // This assumes they won't throw.
      rejectCallbacks.forEach(callback => callback((thenable: any).reason));
      rejectCallbacks.clear();
      callbacks.clear();
    };

    const handleLoadComplete = (durationMs: number): void => {