React 源码浅析之 - 入口文件

本系列文章以 react 最新的版本： 16.0.0-beta.5 为准。
首先我们入口文件 ReactEntry.js 来看，

var ReactBaseClasses = require('ReactBaseClasses');
var ReactChildren = require('ReactChildren');
var ReactElement = require('ReactElement');
var ReactVersion = require('ReactVersion');

var onlyChild = require('onlyChild');

依赖模块：
• ReactBaseClasses
• ReactChildren
• ReactElement
• onlyChild
• ReactElementValidator
接着:

var createElement = ReactElement.createElement;
var createFactory = ReactElement.createFactory;
var cloneElement = ReactElement.cloneElement;

if (__DEV__) {
  var ReactElementValidator = require('ReactElementValidator');
  createElement = ReactElementValidator.createElement;
  createFactory = ReactElementValidator.createFactory;
  cloneElement = ReactElementValidator.cloneElement;
}

可以看到在开发环境下提供了对组件的验证。

var React = {
  Children: {
    map: ReactChildren.map,
    forEach: ReactChildren.forEach,
    count: ReactChildren.count,
    toArray: ReactChildren.toArray,
    only: onlyChild,
  },

  Component: ReactBaseClasses.Component,
  PureComponent: ReactBaseClasses.PureComponent,
  unstable_AsyncComponent: ReactBaseClasses.AsyncComponent,

  createElement: createElement,
  cloneElement: cloneElement,
  isValidElement: ReactElement.isValidElement,

  createFactory: createFactory,

  version: ReactVersion,

  __SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED: {
    ReactCurrentOwner: require('ReactCurrentOwner'),
  },
};

上面这些就是 React 提供的所有 API 了。
我会在后续的文章依次对这些 API 的实现进行解读。

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