ComponentDidMount 本地状态更新

Question

I have someId that I am getting trough the props and I have otherId in the state. Doing this causes infinite loop. I want that if it is the same id to setState , if it's not to do nothing. How can I achieve this?

 componentDidUpdate(prevProps, prevState) {
         if (prevProps.someId === this.state.otherId) {
             this.setState({ ... });
         }
    }

Answer 1

componentDidUpdate(props) {
     if (props.someId !== this.state.otherId) {
             this.setState({ otherId: props.someId });
     }
}

I assume you meant to say: I want that if props.someId is the same as this.state.someId do nothing, if it's not, set it to it...? Or if you want them to be different then just change !== back to === .

Answer 2

My guess is that since you call setState , the component will update again, thus calling the function again endlessly.

Maybe you should use shouldComponentUpdate() instead.

shouldComponentUpdate(nextProps, nextState) {
    return this.props.someId === nextProps.otherId
}

This way, the component will update only if the ids are the same.