一、一个简略的小例子

1. 父组件

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

2. 子组件框架

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}

3. 子组件具体实现

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);
  }
}

这种模式的劣势在于 将父组件与子组件解耦和，父组件能够间接拜访子组件的外部状态而不须要再通过 Props 传递 ，这样父组件 可能更为不便地管制子组件展现的 UI 界面。譬如产品经理让咱们将本来展现的 Badge 替换为 Profile，咱们能够轻易地批改下回调函数即可：

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