react-refetch的使用小例子

出处：《react设计模式和最佳实践》
做者：米凯莱·贝尔托利
出版时间：2018年8月第1版（还算新）

使用react-refetch来简化api获取数据的代码

const List = ({data: gists}) => {
  return (
    <ul>
      {gists.map(gist => (
        <li key={gist.id}>{gist.description}</li>
      ))}
    </ul>
  )
}

const withData = url => Part => {
  return class extends Component {
    state = {data: []}

    componentDidMount() {
      fetch(url)
        .then(response => response.json ? response.json() : response)
        .then(data => this.setState({data}))
    }

    render() {
      return <Part {...this.state} {...this.props} />
    }
  }
}

const ListWithGists = withData('https://api.github.com/users/gaearon/gists')(List)

上面的代码，咱们将api获取数据的逻辑用高阶组件抽离出来，下面咱们再用react-refetch来简化上面的异步代码

import { connect as refetchConnect } from 'react-refetch'

const List = ({gists}) => {
  if (gists.pending) {
    return <div>loading...</div>
  } else if (gists.rejected) {
    return <div>{gists.reason}</div>
  } else if (gists.fulfilled) {
    return (
      gists.fulfilled && <ul>
        {gists.value.map(gist => (
          <li key={gist.id}>{gist.description}</li>
        ))}
      </ul>
    )
  }
}

const ListWithGists = refetchConnect(() => ({gists: `https://api.github.com/users/gaearon/gists`}))(List)

瞬间清爽多了，顺便利用react-refetch提供的属性，顺便把loading逻辑也添加了

分离列表和项目的职责

很明显，List组件是一个渲染列表的组件，他的职责就是渲染列表，可是咱们在这里也处理了单个Item的逻辑，咱们能够将其进行职责分离,List只作列表染，而Gist也只渲染自身

const Gist = ({description}) => (
  <li>
    {description}
  </li>
)

const List = ({gists}) => {
  if (gists.pending) {
    return <div>loading...</div>
  } else if (gists.rejected) {
    return <div>{gists.reason}</div>
  } else if (gists.fulfilled) {
    return (
      gists.fulfilled && <ul>
        {gists.value.map(gist => <Gist key={gist.id} {...gist} />)}
      </ul>
    )
  }
}

使用react-refetch来给Gist添加功能

react-refetch的connect方法接收一个函数做为参数，这个函数返回一个对象，若是结果对象的值是一个字符串，那么获取prop后，会对这个字符串发起请求，可是若是值是一个函数，那么不会当即执行，而是会传递给组件，以便后续使用

值为字符串
const connectWithStar = refetchConnect(() => ({gists: `https://api.github.com/users/gaearon/gists`}))

值为函数
const connectWithStar = refetchConnect(({id}) => ({
  star: () => ({
    starResponse: {
      url: `https://api.github.com/gists/${id}/star?${token}`,
      method: 'PUT'
    }
  })
}))

const Gist = ({description, star}) => (
  <li>
    {description}
    <button onClick={star}>+1</button>
  </li>
)

加工Gist组件，star函数会被传递给Gist的prop，而后就能够在Gist里面使用了
connectWithStar(Gist)