详解React的回调渲染模式

<Twitter username='tylermcginnis33'>
 {(user) => user === null
  ? <Loading />
  : <Badge info={user} />}
</Twitter>

import React, { Component, PropTypes } from 'react'
import fetchUser from 'twitter'
// fetchUser take in a username returns a promise
// which will resolve with that username's data.
class Twitter extends Component {
 // finish this
}

import React, { Component, PropTypes } from 'react';
import fetchUser from 'twitter';
class Twitter extends Component {
 state = {
  user: null,
 }
  static propTypes = {
  username: PropTypes.string.isRequired,
 }
  componentDidMount() {
  fetchUser(this.props.username).then(user => this.setState({user}));
 }
  render() {
  return this.props.children(this.state.user);
 }
}

<Twitter username='tylermcginnis33'>
 {(user) => user === null
  ? <Loading />
  : <Profile info={user} />}
</Twitter>