一、一个简单的小例子
1.父组件


{(user) => user === null

?

: }



{(user) => user === null

?

: }

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
}

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);
}
}

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);
}
}
这种模式的优势在于将父组件与子组件解耦和，父组件可以直接访问子组件的内部状态而不需要再通过 Props 传递，这样父组件能够更为方便地控制子组件展示的 UI 界面。譬如产品经理让我们将原本展示的 Badge 替换为 Profile，我们可以轻易地修改下回调函数即可：

{(user) => user === null

?

: }




{(user) => user === null

?

: }