react 空操作更新列队

该文件当前仅在 ReactBaseClasses 中使用。

一、作用

二、空操作更新列队

/**
 * This is the abstract API for an update queue.
 * 这是用于更新队列的抽象 API。
 */
const ReactNoopUpdateQueue = {
  /**
   * Checks whether or not this composite component is mounted.
   * 检查该复合组件是否已挂载。
   * @param {ReactClass} publicInstance The instance we want to test.
   *                                    我们将测试该实例
   * @return {boolean} True if mounted, false otherwise.
   *                   若挂载完成则返回 true ，否则为假
   * @protected
   * @final
   */
  isMounted: function (publicInstance) {
    return false;
  },

  /**
   * Forces an update. This should only be invoked when it is known with
   * certainty that we are **not** in a DOM transaction.
   * 强制更新。只有在确定我们**不**处于 DOM 事务中时才应调用此方法。
   *
   * You may want to call this when you know that some deeper aspect of the
   * component's state has changed but `setState` was not called.
   *
   * 当你知道组件状态的某些更深层次的方面已经发生变化，但没有调用 `setState` 时，你可能
   * 想调用这个。
   *
   * This will not invoke `shouldComponentUpdate`, but it will invoke
   * `componentWillUpdate` and `componentDidUpdate`.
   *
   * 这不会调用 `shouldComponentUpdate`，但会调用 `componentWillUpdate` 和
   *  `componentDidUpdate`。
   *
   * @param {ReactClass} publicInstance The instance that should rerender.
   *                                    该实例应当渲染
   * @param {?function} callback Called after component is updated.
   *                             在组件更新后调用。
   * @param {?string} callerName name of the calling function in the public API.
   *                             公共 API 中调用函数的名称。
   * @internal
   */
  enqueueForceUpdate: function (publicInstance, callback, callerName) {
    warnNoop(publicInstance, 'forceUpdate');
  },

  /**
   * Replaces all of the state. Always use this or `setState` to mutate state.
   * You should treat `this.state` as immutable.
   * 替换所有的状态。请始终使用此方法或 `setState` 来修改状态。你应该将 `this.state` 视为不可变的。
   *
   * There is no guarantee that `this.state` will be immediately updated, so
   * accessing `this.state` after calling this method may return the old value.
   * 无法保证 `this.state` 会立即更新，因此在调用此方法后访问 `this.state` 可能会返回旧值。
   *
   * @param {ReactClass} publicInstance The instance that should rerender.
   *                                    该实例应当渲染
   * @param {object} completeState Next state.
   *                               下一个状态
   * @param {?function} callback Called after component is updated.
   *                             在组件更新后调用。
   * @param {?string} callerName name of the calling function in the public API.
   *                             公共 API 中调用函数的名称。
   * @internal
   */
  enqueueReplaceState: function (
    publicInstance,
    completeState,
    callback,
    callerName,
  ) {
    warnNoop(publicInstance, 'replaceState');
  },

  /**
   * Sets a subset of the state. This only exists because _pendingState is
   * internal. This provides a merging strategy that is not available to deep
   * properties which is confusing. TODO: Expose pendingState or don't use it
   * during the merge.
   *
   * 设置状态的一个子集。这个存在的唯一原因是 _pendingState 是内部的。这提供了一种对深层属性
   * 不可用的合并策略，这令人困惑。TODO：公开 pendingState 或在合并过程中不要使用它。
   *
   * @param {ReactClass} publicInstance The instance that should rerender.
   *                                     应该重新渲染的实例。
   * @param {object} partialState Next partial state to be merged with state.
   *                              下一个要合并到状态的部分状态。
   * @param {?function} callback Called after component is updated.
   *                             在组件更新后调用。
   * @param {?string} Name of the calling function in the public API.
   *                       在公共 API 中调用函数的函数。
   * @internal
   */
  enqueueSetState: function (
    publicInstance,
    partialState,
    callback,
    callerName,
  ) {
    warnNoop(publicInstance, 'setState');
  },
};

三、常量

// 已警告针对已卸载组件的状态更新
const didWarnStateUpdateForUnmountedComponent = {};

四、工具

// 警告无操作
function warnNoop(publicInstance, callerName) {
  if (__DEV__) {
    const constructor = publicInstance.constructor;
    const componentName =
      (constructor && (constructor.displayName || constructor.name)) ||
      'ReactClass';
    const warningKey = `${componentName}.${callerName}`;
    if (didWarnStateUpdateForUnmountedComponent[warningKey]) {
      return;
    }
    console.error(
      "Can't call %s on a component that is not yet mounted. " +
        'This is a no-op, but it might indicate a bug in your application. ' +
        'Instead, assign to `this.state` directly or define a `state = {};` ' +
        'class property with the desired state in the %s component.',
      callerName,
      componentName,
    );
    didWarnStateUpdateForUnmountedComponent[warningKey] = true;
  }
}