All about the new React Hook: useOptimistic

React, the JavaScript library for building user interfaces, continues to evolve.

With the release of React 19, the team behind React has gone even further in improving the user experience by introducing an entirely new hook: useOptimistic.

This hook aims to enhance relative interface update performance after adding, modifying, or deleting information.

What is the useOptimistic hook? 🤔

The useOptimistic hook allows immediate updates to the user interface without waiting for server confirmation. This is known as an optimistic update.

It provides better responsiveness to the user by assuming the action will succeed without encountering errors.

Why use useOptimistic? 👀

The primary goal of useOptimistic is to enhance the responsiveness of a web application. Imagine an app where a user has to wait several seconds after clicking a button due to network latency...

With useOptimistic, you can respond instantly to user actions while handling potential errors later.

Essentially, you update the interface before sending the changes to your server, providing a smoother experience.

How does useOptimistic work? 🛠️

useOptimistic is designed to perform an immediate update while keeping the previous state (or state) in memory, allowing you to revert in case of an issue.

Here’s how you can use it! 😉

Underlying Logic

The diagram below explains how useOptimistic works:

Step 1: User action (e.g., adding a message)
↓
Step 2: Immediate UI update
↓
Step 3: Send data to the server (performed in the background)
↓
Step 4: If server responds successfully → Keep updated state
         Else → Revert to the original state

Basic Syntax

Here’s an example of the basic syntax for the useOptimistic hook:

const [optimisticValue, updateOptimistic] = useOptimistic(initialState, (currentState, newState) => {
  return newState;
});

Explanation:

• optimisticValue: The value to use in your JSX code.
• updateOptimistic: A function that triggers an optimistic update (similar to a function from the useState hook, but it performs optimistic updates).
• initialState: The original state.
• currentState and newState: The two states to merge.

Example Usage

Let’s take an example of an app where a user adds a message to a chat. With useOptimistic, the message is immediately visible on the screen, even before the server response is received.

This creates a very smooth application with a sense of instantaneousness, greatly enhancing user experience.

function MessageSection() {
  const [messages, updateOptimistic] = useOptimistic([], (prevMessages, newMessage) => [
    ...prevMessages,
    newMessage
  ]);

  const handleAddMessage = async (newMessage) => {
    updateOptimistic(newMessage);

    try {
      await fetch("...");
    } catch (error) {
      console.error("Error:", error);
    }
  };

  return (
    <div>
      <ul>
        {messages.map((message, index) => (
          <li key={index}>{message}</li>
        ))}
      </ul>
      <button onClick={() => handleAddMessage("New message")}>
        Add Message
      </button>
    </div>
  );
}

Advantages of useOptimistic ✅

Improved User Experience

As shown, useOptimistic improves user experience by eliminating the frustrating wait between the time a user triggers an action (like clicking a button to submit a form) and the interface update after a server response.

With useOptimistic, the interface reacts immediately!

Simplified Error Handling

In the event of a server or update issue, useOptimistic makes it easy to revert to the previous state. It handles this for you, eliminating the need to write extensive logic for UI updates.

Common Use Cases 📝

Here are some scenarios where immediate UI updates would greatly enhance your website:

• Instant interactions (like likes, shares, or favorites).
• Article updates (or general post updates).
• Chat applications.

useOptimistic vs. useState 💥

The useOptimistic and useState hooks both handle data management in a React application. However, they serve different purposes and behave distinctly.

The table below summarizes their differences:

Conclusion

The useOptimistic hook is a powerful and effective feature introduced in React 19 to improve interactivity and fluidity.

When used in the right scenarios, it provides a significant competitive edge.

If you want to learn more about React, click here! 👈

FAQ 👇

Here are some common questions about useOptimistic from our learners:

Why should I use useOptimistic?

To make your application more responsive! For example, imagine a comments section—it’s much better if the user doesn’t have to wait to see their comment.

Can useOptimistic be combined with other hooks?

Yes, you can use it with other hooks like useReducer for more complex scenarios.

What are the best use cases for useOptimistic?

You can use useOptimistic for buttons to modify, add, or delete something. Any feature that improves the user experience with instantaneous feedback is a great candidate for useOptimistic.

How can I learn more about React? Which course should I choose?

There are many options, but ours might be a great choice if you enjoyed this article! 😋