Trigger some API once react state empty-CodePudding

I want to trigger An API to do some actions when the value in the react state be empty, Is there a way in react state hook to achieve that?

CodePudding user response：

If you are using a functional component you can use the "useEffect" hook with a proper dependency. Class base components you might choose (if I understand your situation properly) something like the "componentWillUnmount()" method.

CodePudding user response：

You could have a useEffect hook with the state as a dependency, in-which you can check if the state is empty and act accordingly.

Example:

const [state, setState] = useState([]);

useEffect(() => {
   if (state.length !== 0) {
      return;
   }
   // Can make your API call here (preferably call a function that does it)
   // and then set the state.
   setState(...);
}, [state]);

useEffect is a hook that accepts a callback as the first argument, and a dependency array as the second.
The callback will execute upon re-render whenever any of the dependencies in the array change.

Note: this is relevant only for functional components, for class-based component we have the componentDidUpdate lifecycle hook.