javascript - 等待每个完成在 react 中使用 setState

Question

如何等待 foreach 中的 setState 完成然后显示渲染？

class App extends Component {
  componentDidMount() {
    someArrOfObject.forEach(o => {
      this.setState({
        [`list_for_${o.id}`]: o.val
      })
    })
  }

  render() {

    const { selected_id } = this.state
    const selected_list = this.state[`list_for_${selected_id}`]

    return selected_list.map(o => <div>{o.val}</div>)
  }
}

Answer 1

class App extends Component {
  componentDidMount() {
    let newState = {};
    someArrOfObject.forEach(o => {
      {
        newState[`list_for_${o.id}`] = o.val;
      })
    })
    this.setState(newState);
  } 
  render() {

    const { selected_id } = this.state
    const selected_list = this.state[`list_for_${selected_id}`]

    return selected_list.map(o => <div>{o.val}</div>)
  }
}