Function enqueueForceUpdate

packages/react-reconciler/src/ReactFiberClassComponent.js:218–242

(inst: any, callback)

  },
  // $FlowFixMe[missing-local-annot]
  enqueueForceUpdate(inst: any, callback) {
    const fiber = getInstance(inst);
    const lane = requestUpdateLane(fiber);

    const update = createUpdate(lane);
    update.tag = ForceUpdate;

    if (callback !== undefined && callback !== null) {
      if (__DEV__) {
        warnOnInvalidCallback(callback);
      }
      update.callback = callback;
    }

    const root = enqueueUpdate(fiber, update, lane);
    if (root !== null) {
      startUpdateTimerByLane(lane, 'this.forceUpdate()', fiber);
      scheduleUpdateOnFiber(root, fiber, lane);
      entangleTransitions(root, fiber, lane);
    }

    if (enableSchedulingProfiler) {
      markForceUpdateScheduled(fiber, lane);
    }
  },
};

function checkShouldComponentUpdate(