Resolving React Component Not Re-rendering After Updating State with useState

Discover the solution to the common issue of React components not re-rendering after state changes with `useState` and `useEffect`. Learn how to effectively manage asynchronous data fetching and state updates.
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Understanding the React Re-rendering Issue

One of the common challenges developers face while working with React is ensuring that components re-render correctly after state updates. If you're using the useState and useEffect hooks to manage and fetch data, you might find yourself in a situation where your component does not re-render even when state changes occur. In this guide, we will dive into a particular scenario involving the useState hook, asynchronous functions, and why the component might not re-render as expected.

The Problem

Imagine you have a React component that relies on a state variable to display an array of objects fetched asynchronously. You've set up your state with useState, and you're using useEffect to fetch data whenever certain dependencies change. However, even after your state updates with the new data, the component doesn't re-render to reflect these changes. You see the expected data in console logs but not in your UI. This situation can be frustrating, so let’s explore why this happens and how to resolve it.

The Current Implementation

Here's a basic outline of how the problematic code looks:

[[See Video to Reveal this Text or Code Snippet]]

Despite updates to campaignRewardsJson, you notice the component does not re-render. Let's analyze why.

Why the Component Does Not Re-render

The key issue lies within the getRewardObject function. The original method of using map() on rewards does not wait for the asynchronous operations to complete before returning. This leads to an incomplete array being pushed into campaignRewardsJson, causing the rendering issue.

[[See Video to Reveal this Text or Code Snippet]]

Updates Explained:

Rendering the Updated Data

Now, with the correct implementation, your component will successfully re-render when the data in campaignRewardsJson updates. You should see the rendered output in your UI as intended:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Hopefully, this guide has clarified why your React component wasn't re-rendering and provided you with a solid solution to tackle this issue in the future.