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Debouncing vs useDefferedValue

Debouncing and useDeferredValue are both techniques used in web development to optimize performance and user experience, especially when dealing with expensive or frequently updating operations. However, they serve slightly different purposes and are associated with different technologies.


Purpose: Debouncing is a technique used to control the rate at which a function is called. It's often used in scenarios where a function is called multiple times in rapid succession (such as with event handlers) and you want to ensure that it's executed only once, after a specific quiet period.

Use Cases: Common use cases include implementing search-as-you-type functionality, handling scroll events, or any situation where you want to avoid rapid, redundant function calls.

Implementation: Typically, you use a JavaScript library or write custom code to debounce a function. This involves setting a timer that delays the execution of the function and resets the timer every time the function is called before the timer expires.

function debounce(func, delay) {
  let timerId;
  return function (...args) {
    timerId = setTimeout(() => {
      func.apply(this, args);
    }, delay);
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Purpose: useDeferredValue is a hook introduced in React 18 and is used specifically with concurrent mode. Its purpose is to defer the rendering and processing of updates to improve the user experience by avoiding interruptions during user interactions or animations.

Use Cases: It's particularly useful in scenarios where you have animations or interactions that might otherwise be affected by the concurrent rendering and scheduling nature of React.

Implementation: You use useDeferredValue in combination with other React Concurrent features, like Suspense and useTransition. It's part of the Suspense API and allows you to defer the update of a value until the next render cycle, helping to reduce jank and improve perceived performance.

const deferredValue = useDeferredValue(value, { timeoutMs: 1000 });
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Purpose: Debouncing is a general-purpose technique to control the rate of function calls, while useDeferredValue is specific to React Concurrent mode and is used to optimize rendering for improved user experience.

Use Cases: Debouncing is used for handling user input, events, and other situations where you want to avoid rapid function execution. useDeferredValue is used in React applications to optimize rendering in concurrent mode.

Implementation: Debouncing can be implemented using JavaScript timers. useDeferredValue is a React hook that integrates with concurrent mode features like Suspense and should be used in React applications.

In summary, while debouncing is a more general-purpose technique to control the rate of function calls, useDeferredValue is a React-specific optimization tool designed for use with concurrent mode to improve rendering performance and user experience in React applications. They serve different purposes and are applied in different contexts.

Top comments (1)

mrottimista profile image
Adel Emad

Great effort,
but this article has many mistakes, for example:

  1. you mentioned that Debouncing is better for search-as-you-type functionality; however, useDeferedValue is better for some reasons that will be mentioned in the link below. You can find that React docs use it in an example for the same scenario.
  2. You mentioned in the second code snippet that useDeferredValue takes timeout which is not right at all.

React made this comparison in its docs so I prefer to get back to it