finishClassComponent() — react Function Reference

Source Code

packages/react-reconciler/src/ReactFiberBeginWork.js lines 1688–1780

function finishClassComponent(
  current: Fiber | null,
  workInProgress: Fiber,
  Component: any,
  shouldUpdate: boolean,
  hasContext: boolean,
  renderLanes: Lanes,
) {
  // Refs should update even if shouldComponentUpdate returns false
  markRef(current, workInProgress);

  const didCaptureError = (workInProgress.flags & DidCapture) !== NoFlags;

  if (!shouldUpdate && !didCaptureError) {
    // Context providers should defer to sCU for rendering
    if (hasContext) {
      invalidateContextProvider(workInProgress, Component, false);
    }

    return bailoutOnAlreadyFinishedWork(current, workInProgress, renderLanes);
  }

  const instance = workInProgress.stateNode;

  // Rerender
  if (__DEV__) {
    setCurrentFiber(workInProgress);
  }
  let nextChildren;
  if (
    didCaptureError &&
    typeof Component.getDerivedStateFromError !== 'function'
  ) {
    // If we captured an error, but getDerivedStateFromError is not defined,
    // unmount all the children. componentDidCatch will schedule an update to
    // re-render a fallback. This is temporary until we migrate everyone to
    // the new API.
    // TODO: Warn in a future release.
    nextChildren = null;

    if (enableProfilerTimer) {
      stopProfilerTimerIfRunning(workInProgress);
    }
  } else {
    if (enableSchedulingProfiler) {
      markComponentRenderStarted(workInProgress);
    }
    if (__DEV__) {
      nextChildren = callRenderInDEV(instance);
      if (workInProgress.mode & StrictLegacyMode) {
        setIsStrictModeForDevtools(true);
        try {
          callRenderInDEV(instance);
        } finally {
          setIsStrictModeForDevtools(false);
        }
      }
    } else {
      nextChildren = instance.render();
    }
    if (enableSchedulingProfiler) {
      markComponentRenderStopped();
    }
  }

  // React DevTools reads this flag.
  workInProgress.flags |= PerformedWork;
  if (current !== null && didCaptureError) {
    // If we're recovering from an error, reconcile without reusing any of
    // the existing children. Conceptually, the normal children and the children
    // that are shown on error are two different sets, so we shouldn't reuse
    // normal children even if their identities match.
    forceUnmountCurrentAndReconcile(
      current,
      workInProgress,
      nextChildren,
      renderLanes,
    );
  } else {
    reconcileChildren(current, workInProgress, nextChildren, renderLanes);
  }