Optimistic Updates in React with TypeScript

Optimistic updates are a UI pattern where the application immediately reflects the expected outcome of an action, even before the server confirms it. This creates a more responsive and fluid user experience, making the application feel faster.

How Optimistic Updates Work

When a user performs an action (like adding an item to a cart or marking a task as complete), the UI is updated instantly to show the change. Simultaneously, a request is sent to the server to persist this change. If the server request succeeds, the UI remains as is. If it fails, the UI is rolled back to its previous state, and an error message is displayed.

Immediate UI feedback for a faster feel.

Instead of waiting for server confirmation, the UI shows the change right away. This makes the app feel snappier.

The core principle is to provide immediate visual feedback to the user. When a user clicks a button to, for example, 'like' a post, the 'like' count increments and the button visually changes to indicate it's been 'liked'. This happens before the server has even processed the request. This technique significantly improves perceived performance, as users don't have to stare at a loading spinner or wait for a response before seeing the result of their action.

Benefits of Optimistic Updates

The primary benefit is an enhanced user experience due to improved perceived performance. Users feel like the application is more responsive and interactive. It can also reduce the perceived latency of network requests.

Think of it like telling your friend you're bringing a dish to a potluck before you've even bought the ingredients. You're acting as if it's done, and if you can't make it, you'll let them know.

Implementing Optimistic Updates with React and TypeScript

In React, optimistic updates are typically managed using state management libraries like Redux, Zustand, or even React's built-in

code

useState

and

code

useReducer

hooks. The process involves:

Updating the local state immediately.
Making the API call.
Handling the API response: If successful, do nothing further. If failed, revert the local state and show an error.

Consider a scenario where a user marks a to-do item as complete.

Local State Update: The completed status of the item in the component's state is immediately set to true. The UI reflects this change (e.g., a strikethrough on the text).
API Call: An asynchronous request (e.g., using fetch or axios) is sent to the server to update the item's status.
Success Handling: If the API call returns a success status (e.g., 200 OK), the local state remains as is.
Error Handling: If the API call fails (e.g., network error, server error), the local state is reverted to its previous value (e.g., completed: false), and an error message is displayed to the user.

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Handling Errors and Rollbacks

A critical part of optimistic updates is robust error handling. When an API request fails, it's essential to revert the UI to its previous state to maintain data consistency. This rollback mechanism ensures that the user isn't left with an incorrect representation of the data. Clear error messages should be displayed to inform the user about the failure and guide them on potential next steps.

What is the main advantage of using optimistic updates in a user interface?

Improved perceived performance and a more responsive user experience.

What must be done if an API request initiated by an optimistic update fails?

The UI must be reverted to its previous state, and an error message should be displayed to the user.

Learning Resources

Optimistic UI: A Guide to Better User Experience(blog)

This blog post provides a comprehensive overview of optimistic UI patterns, their benefits, and implementation strategies.

Optimistic Updates: A Pattern for Faster UIs(blog)

Kent C. Dodds explains the concept of optimistic updates and how to implement them effectively in web applications.

React Query Docs: Optimistic Updates(documentation)

Official documentation for React Query, detailing how to implement optimistic updates with this popular data-fetching library.

How to Implement Optimistic Updates in React(blog)

A practical guide on implementing optimistic updates in React applications, covering common patterns and considerations.

Understanding Optimistic UI Updates(blog)

Robin Wieruch's blog post delves into the concept of optimistic UI updates and provides code examples for React.

Optimistic Updates with Apollo Client(documentation)

Learn how to implement optimistic UI updates specifically when using Apollo Client for GraphQL data fetching in React.

Building a Better User Experience with Optimistic UI(blog)

This article explores the impact of optimistic UI on user experience and offers practical advice for implementation.

Optimistic Updates in Redux Toolkit(documentation)

Guidance on implementing optimistic updates when using Redux Toolkit for state management in React applications.

The Art of Optimistic UI(blog)

A UX-focused article discussing the design principles and user benefits of employing optimistic UI patterns.

Optimistic Updates: A React Tutorial(video)

A video tutorial demonstrating how to implement optimistic updates in a React application, often with practical code examples.