Function updateFunctionalComponent

code/event-handlers/public/app.js:9155–9186

(current, workInProgress)

  }

  function updateFunctionalComponent(current, workInProgress) {
    var fn = workInProgress.type;
    var nextProps = workInProgress.pendingProps;

    if (hasLegacyContextChanged()) {
      // Normally we can bail out on props equality but if context has changed
      // we don't do the bailout and we have to reuse existing props instead.
    } else {
      if (workInProgress.memoizedProps === nextProps) {
        return bailoutOnAlreadyFinishedWork(current, workInProgress);
      }
      // TODO: consider bringing fn.shouldComponentUpdate() back.
      // It used to be here.
    }

    var unmaskedContext = getUnmaskedContext(workInProgress);
    var context = getMaskedContext(workInProgress, unmaskedContext);

    var nextChildren = void 0;

    {
      ReactCurrentOwner.current = workInProgress;
      ReactDebugCurrentFiber.setCurrentPhase('render');
      nextChildren = fn(nextProps, context);
      ReactDebugCurrentFiber.setCurrentPhase(null);
    }
    // React DevTools reads this flag.
    workInProgress.effectTag |= PerformedWork;
    reconcileChildren(current, workInProgress, nextChildren);
    memoizeProps(workInProgress, nextProps);
    return workInProgress.child;
  }

  function updateClassComponent(current, workInProgress, renderExpirationTime) {
    // Push context providers early to prevent context stack mismatches.