React - componentWillReceiveProps alternative [duplicate]

问题

I use React with NextJS.

I have a component which is basically a table which gives some summary. Based on some UI selection, this component is expected to show appropriate summary.

The below code works perfectly fine.

class Summary extends Component{

    state = {
        total: 0,
        pass: 0,
        fail: 0,
        passp: 0,
        failp: 0
    }

    componentWillReceiveProps(props){
        let total = props.results.length;
        let pass  = props.results.filter(r => r.status == 'pass').length;
        let fail  = total - pass;
        let passp = (pass/(total || 1) *100).toFixed(2);
        let failp = (fail/(total || 1) *100).toFixed(2);
        this.setState({total, pass, fail, passp, failp});
    }

    render() {
        return(
          <Table color="teal" >
                <Table.Header>
                  <Table.Row textAlign="center">
                    <Table.HeaderCell>TOTAL</Table.HeaderCell>
                    <Table.HeaderCell>PASS</Table.HeaderCell>
                    <Table.HeaderCell>FAIL</Table.HeaderCell>
                    <Table.HeaderCell>PASS %</Table.HeaderCell>
                    <Table.HeaderCell>FAIL %</Table.HeaderCell>                                 
                  </Table.Row>
                </Table.Header>
                <Table.Body>
                  <Table.Row textAlign="center">
                    <Table.Cell>{this.state.total}</Table.Cell>
                    <Table.Cell >{this.state.pass}</Table.Cell>
                    <Table.Cell >{this.state.fail}</Table.Cell>                                     
                    <Table.Cell >{this.state.passp}</Table.Cell>
                    <Table.Cell >{this.state.failp}</Table.Cell>                                      
                  </Table.Row>
                </Table.Body>
           </Table>             
        );
    }
}

Looks like componentWillReceiveProps will be deprecated. I tried other options like shouldComponentUpdate etc..they all lead to infinite loop. What is best approach to update the state from the props to re-render this component?

回答1:

From react blog, 16.3 introduced deprecation notices for componentWillRecieveProps.

As a workaround, you would use the method

static getDerivedStateFromProps(nextProps, prevState)

therefore

componentWillReceiveProps(props){
    let total = props.results.length;
    let pass  = props.results.filter(r => r.status == 'pass').length;
    let fail  = total - pass;
    let passp = (pass/(total || 1) *100).toFixed(2);
    let failp = (fail/(total || 1) *100).toFixed(2);
    this.setState({total, pass, fail, passp, failp});
}

becomes

static getDerivedStateFromProps(nextProps, prevState) {
  if (nextProps.total !== prevState.total) {
    return ({ total: nextProps.total }) // <- this is setState equivalent
  }
  etc...
}

来源：https://stackoverflow.com/questions/50692160/react-componentwillreceiveprops-alternative

标签

reactjs

nextjs