text: 
  import { Children } from 'react-core/Children';
  import { PropTypes } from 'react-core/PropTypes';
  import { Component } from 'react-core/Component';
  import { PureComponent } from 'react-core/PureComponent';
  import { createRef, forwardRef } from 'react-core/createRef';
  import { createPortal } from 'react-core/createPortal';
  import { createContext } from 'react-core/createContext';
  import { createElement,cloneElement, isValidElement, createFactory } from 'react-core/createElement';
  import { Fragment, getWindow } from 'react-core/util';
  
  import { NoopRenderer} from './NoopRenderer';
  
  var win = getWindow();
  var prevReact = win.ReactNoop;
  let ReactNoop;
  if (prevReact && prevReact.isReactNoop) {
      ReactNoop = prevReact; //解决引入多个
  } else {
      let {render, flush, reset, getRoot, getChildren} = NoopRenderer;
      ReactNoop = win.ReactNoop = { //放出全局的ReactNoop
          //平台相关API
          yield: NoopRenderer.yield,
          flush,
          reset,
          getRoot,
          getChildren,
          isReactNoop: true,
          //ReactFiber API
          version: 'VERSION',
          render,
          Fragment,
          PropTypes,
          Children,
          createPortal,
          createContext,
          Component,
          createRef,
          forwardRef,
          createElement,
          cloneElement,
          PureComponent,
          isValidElement,
          createFactory
      };
  }
  export default ReactNoop;
  