react async loading data

class Post extends Component {
  constructor () {
    super()
    this.state = { content: '' }
  }
  
  componentWillMount () {
    this._loadData()
  }
  
  async _loadData () {
    this.setState({ content: '数据加载中...' })
    const content = await getPostData()
    this.setState({ content })
  }
  
  render () {
    return (
      <div>
        <div className='post-content'>{this.state.content}</div>
        <button onClick={() => {
          this._loadData()
        }}>刷新</button>
      </div>
    )
  }
}