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>