How to use a React state immediatley after dispatch()
Redux is a powerful state manager but its good to know its side effects.
Recently I encountered an issue where I needed to use a state right after dispatching an action that updates it using redux-toolkit.
PermalinkProblem
When an action is dispatched in Redux, the store is updated asynchronously, which means that the updated state may not be immediately available in the component that dispatched the action.
PermalinkSolution
Use a reference to the state using useRef hook and leverage useEffect which makes use of the fact that the component will re-render after the state is changed.
Inside the useEffect you can update the ref and use that ref from now on.
PermalinkCode
import { useRef, useEffect } from 'react';
import { useDispatch, useSelector } from 'react-redux';
import { increment } from './counterSlice'; // assuming you have a counterSlice that contains an "increment" action
function Counter() {
const count = useSelector((state) => state.counter.value);
const dispatch = useDispatch();
const counterRef = useRef(count); // create a mutable reference to the initial count value
useEffect(() => {
counterRef.current = count; // update the reference when count changes
}, [count]);
const handleIncrement = () => {
dispatch(increment());
const updatedCount = counterRef.current; // use the updated value from the reference
someFunction(updatedCount); // pass the updated count value to another function
};
return (
<div>
<h1>Count: {count}</h1>
<button onClick={handleIncrement}>Increment</button>
</div>
);
}
export default Counter;