Throttling is a technique used to limit the number of times a function is called or a side effect is triggered within a certain time period. It is useful in scenarios where you want to optimize performance or prevent overloading an API.

In this article, we will explore how to create a custom useThrottleEffect hook using React’s useEffect and throttle function from the lodash library.

Table of Contents

• Introduction
• Implementation
• Usage
• Conclusion

Introduction

React provides the useEffect hook for handling side effects within functional components. By default, the useEffect hook runs on every render cycle, but with the ability to specify dependencies, you can control when it should run.

However, in some cases, you may want to limit the number of times a side effect is triggered within a specific time period, such as when dealing with expensive API calls or handling user input. This is where the useThrottleEffect hook comes in handy.

Implementation

Let’s start by creating a new file named useThrottleEffect.js and define our custom hook.

import { useEffect, useRef } from 'react';
import throttle from 'lodash/throttle';

const useThrottleEffect = (effect, delay, dependencies) => {
  const throttleEffect = useRef(throttle(effect, delay));

  useEffect(() => {
    const throttledEffect = throttleEffect.current;

    return () => {
      throttledEffect.cancel();
    };
  }, dependencies);

  useEffect(() => {
    if (delay === 0) {
      effect();

      return undefined;
    }

    const throttledEffect = throttleEffect.current;

    throttledEffect();

    return () => {
      throttledEffect.cancel();
    };
  }, dependencies);
};

export default useThrottleEffect;

In our implementation, we import the necessary dependencies: useEffect, useRef, and the throttle function from the lodash library. We create a ref for the throttled effect using useRef to ensure its persistence between renders.

The core logic of our custom hook is within two useEffect hooks. The first useEffect registers a cleanup function that cancels the throttled effect when dependencies change. This ensures that the throttled effect is properly canceled when the component unmounts or when the dependencies change.

The second useEffect checks if the delay is set to zero. If it is, it immediately invokes the effect function. If not, it invokes the throttled effect and returns a cleanup function that cancels the throttled effect.

Usage

Now that we have our useThrottleEffect hook implemented, we can use it in our functional components.

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

const ExampleComponent = () => {
  const handleScroll = () => {
    console.log('Scroll event throttled with a 500ms delay');
  };

  useThrottleEffect(handleScroll, 500, []);

  return (
    <div>
      {/* Component content */}
    </div>
  );
};

export default ExampleComponent;

In this example, we create an ExampleComponent that logs a message to the console whenever a scroll event occurs. We pass handleScroll as the effect function to useThrottleEffect, along with a delay of 500 milliseconds and an empty dependency array.

This ensures that the handleScroll function is invoked at most once every 500 milliseconds, preventing it from being triggered too frequently.

Conclusion

Throttling side effects can be a useful technique for optimizing performance and preventing overload in certain scenarios. By creating a custom useThrottleEffect hook, we can easily incorporate throttling into our React components.

In this article, we explored how to create a custom useThrottleEffect hook using React’s useEffect and the throttle function from the lodash library. This allows us to control when and how often a side effect is triggered within a specified time period.

Remember to use throttling sparingly and consider the impact on user experience. It’s best suited for scenarios where performance optimization is crucial or when you need to limit the frequency of certain actions.