Function updateContextConsumer

packages/react-reconciler/src/ReactFiberBeginWork.js:3634–3674

(
  current: Fiber | null,
  workInProgress: Fiber,
  renderLanes: Lanes,
)

}

function updateContextConsumer(
  current: Fiber | null,
  workInProgress: Fiber,
  renderLanes: Lanes,
) {
  const consumerType: ReactConsumerType<any> = workInProgress.type;
  const context: ReactContext<any> = consumerType._context;
  const newProps = workInProgress.pendingProps;
  const render = newProps.children;

  if (__DEV__) {
    if (typeof render !== 'function') {
      console.error(
        'A context consumer was rendered with multiple children, or a child ' +
          "that isn't a function. A context consumer expects a single child " +
          'that is a function. If you did pass a function, make sure there ' +
          'is no trailing or leading whitespace around it.',
      );
    }
  }

  prepareToReadContext(workInProgress, renderLanes);
  const newValue = readContext(context);
  if (enableSchedulingProfiler) {
    markComponentRenderStarted(workInProgress);
  }
  let newChildren;
  if (__DEV__) {
    newChildren = callComponentInDEV(render, newValue, undefined);
  } else {
    newChildren = render(newValue);
  }
  if (enableSchedulingProfiler) {
    markComponentRenderStopped();
  }

  // React DevTools reads this flag.
  workInProgress.flags |= PerformedWork;
  reconcileChildren(current, workInProgress, newChildren, renderLanes);
  return workInProgress.child;
}

function updateScopeComponent(
  current: null | Fiber,