How to Implement Forceupdate in React Hooks

This may be useful in some cases.

Photo by Ian Cylkowski on Unsplash

React hooks have revolutionized the way we write components in React. With the introduction of hooks, we now have a way to reuse stateful logic without having to use class components. One of the most popular hooks in React is useState, which provides a way to manage the state in functional components. However, one limitation of useState is that it doesn't provide a way to force a re-render of a component. In this article, we'll explore how to implement forceUpdate in React hooks.

Before we dive into the implementation, it’s important to understand why we would want to use forceUpdate. Sometimes, we may have a component that needs to be updated even if its state hasn't changed. This can happen when we want to re-render a component based on a prop change or when we want to update the component after an asynchronous operation completes. In these cases, we can use forceUpdate to force a re-render of the component.

In class components, we can call forceUpdate to trigger a re-render. However, in functional components using hooks, there is no equivalent method. To implement forceUpdate in functional components, we can use the useReducer hook.

The useReducer hook provides a way to manage state in functional components similar to useState. However, instead of returning a state and a function to update the state, it returns a state and a dispatch function that can be used to update the state. We can use this dispatch function to trigger a re-render of the component.

Here’s an example implementation of forceUpdate using useReducer:

import { useReducer } from 'react';

function useForceUpdate() {
  const [, forceUpdate] = useReducer(x => x + 1, 0);
  return forceUpdate;
}

In this implementation, we use useReducer to create a state variable that doesn't actually store any data. Instead, it just increments a counter every time the dispatch function is called. We then return the dispatch function as the forceUpdate function.

To use useForceUpdate in a component, we can call it to get the forceUpdate function, which can be used to trigger a re-render of the component:

import React from 'react';
import useForceUpdate from './useForceUpdate';

function MyComponent(props) {
  const forceUpdate = useForceUpdate();
  // ...
  return (
    <div>
      {/* ... */}
      <button onClick={forceUpdate}>Force Update</button>
    </div>
  );
}

By using useReducer and a custom hook, we can implement forceUpdate in functional components using hooks. This can be a useful technique when we need to trigger a re-render of a component based on something other than state changes.

Also, if you don’t like the count being incremented, we can return a {} each time, like this:

import { useReducer } from 'react';

function useForceUpdate() {
  const [, forceUpdate] = useReducer(() => ({}), {});
  return forceUpdate;
}

It’s important to note that using forceUpdate should be done sparingly and only when necessary. In most cases, React's built-in rendering logic is sufficient and there's no need to force a re-render. Overusing forceUpdate can lead to unnecessary re-renders and hurt performance.

In addition to forceUpdate, there are other techniques we can use to trigger a re-render of a component in functional components. One common technique is to use a key prop on a component to force a re-render when a prop changes. For example, if we have a component that displays a user's name, we can pass the user's ID as a key prop. When the user's ID changes, React will re-mount the component and trigger a re-render.

import React from 'react';

function User(props) {
  // ...
}

function App() {
  const [userId, setUserId] = useState(1);
  const handleClick = () => setUserId(userId + 1);
  return (
    <div>
      <User key={userId} userId={userId} />
      <button onClick={handleClick}>Next User</button>
    </div>
  );
}

In this example, we pass the userId as a key prop to the User component. When the Next User button is clicked, the userId state is incremented, which triggers a re-render of the User component.

In summary, please use forced rendering with caution, unless you know why you want to do it, in some cases you can consider adding key props instead.

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