@antv/f-engine/lib/component/updater.js

FEngine 是 AntV F 系列可视化引擎的底层渲染引擎，为移动端提供了一套完整的渲染、事件、动画能力，能方便的构建可视化 UI

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.createUpdater = createUpdater;
function createUpdater(canvas) {
  var setStateQueue = [];
  function process() {
    var item;
    var renderComponents = [];
    var renderCallbackQueue = [];
    while (item = setStateQueue.shift()) {
      var state = item.state,
        component = item.component,
        callback = item.callback;
      // 组件已销毁，不再触发 setState
      if (component.destroyed) {
        continue;
      }
      // 如果没有prevState，则将当前的state作为初始的prevState
      if (!component.prevState) {
        component.prevState = Object.assign({}, component.state);
      }
      // 如果stateChange是一个方法，也就是setState的第二种形式
      if (typeof state === 'function') {
        Object.assign(component.state, state(component.prevState, component.props));
      } else {
        // 如果stateChange是一个对象，则直接合并到setState中
        Object.assign(component.state, state);
      }
      component.prevState = component.state;
      if (typeof callback === 'function') {
        renderCallbackQueue.push({
          callback: callback,
          component: component
        });
      }
      if (renderComponents.indexOf(component) < 0) {
        renderComponents.push(component);
      }
    }
    canvas.updateComponents(renderComponents);
    // callback queue
    commitRenderQueue(renderCallbackQueue);
  }
  function enqueueSetState(component, state, callback) {
    if (setStateQueue.length === 0) {
      setTimeout(process, 0);
    }
    setStateQueue.push({
      component: component,
      state: state,
      callback: callback
    });
  }
  function commitRenderQueue(callbackQueue) {
    for (var i = 0; i < callbackQueue.length; i++) {
      var _a = callbackQueue[i],
        callback = _a.callback,
        component = _a.component;
      callback.call(component);
    }
  }
  var updater = {
    // isMounted: function(publicInstance) {
    //   return false;
    // },
    enqueueForceUpdate: enqueueSetState,
    // enqueueReplaceState: function(publicInstance, completeState) {
    // },
    enqueueSetState: enqueueSetState
  };
  return updater;
}