React 两种Context 用法

第一种 childContextTypes

 // 父组件

import React from 'react'
import PropTypes from 'prop-types'
import Test from './Test'

class Main extends React.Component {
  state = {
    a: 111111111
  }

  getChildContext() {
    return {
      a: this.state.a
    }
  }

  render() {
    return (
      <Test />
    )
  }
}

Main.childContextTypes = {
  a: PropTypes.number,
}


// 子组件

import React from 'react'
import PropTypes from 'prop-types'

class Test extends React.Component {
  render() {
    console.log(this.context.a)
    return (
      <div>TestTestTest</div>
    )
  }
}

Test.contextTypes = {
  a: PropTypes.number
}

export default Test;

export default Main;

第二种 React.createContext(default,fn)