Debouncing in JavaScript

Debouncing in JavaScript

Debouncing is a technique used in programming to optimize the performance of web applications by controlling the frequency at which functions are executed.

In this article, we will explore the concept of debouncing, understand its benefits, and walk through how to implement it in JavaScript with practical code examples.

What is Debouncing ?

Debouncing is a method of postponing the execution of a function until a specified delay period has passed since its last invocation.

This technique is especially helpful in situations where we want to prevent excessive or redundant function calls, which can be resource-intensive or slow down performance.

For instance, consider a search bar that displays suggestions as the user types.

If we trigger a function to fetch suggestions on every keystroke, it could result in a flood of requests to the server, leading to performance issues and unnecessary resource consumption.

By applying debouncing, we can delay the request until the user has stopped typing for a brief period, ensuring that the request is made only once after they’ve finished typing.

This prevents excessive server calls and enhances the overall efficiency of the application.

How to implement debouncing in JavaScript?

There are several ways to implement debouncing in JavaScript, but a common and effective approach is to create a wrapper function.

This wrapper returns a new function that delays the execution of the original function.

The key part is that the wrapper function manages a timer variable, which helps to clear or reset the delay each time the new function is called.

This ensures that the original function is only executed after a specified delay, and any previous executions are canceled if the function is called again before the delay period ends.

const debounce = (mainFunction, delay) => {
  // Declare a variable called 'timer' to store the timer ID
  let timer;

  // Return an anonymous function that takes in any number of arguments
  return function (...args) {
    // Clear the previous timer to prevent the execution of 'mainFunction'
    clearTimeout(timer);

    // Set a new timer that will execute 'mainFunction' after the specified delay
    timer = setTimeout(() => {
      mainFunction(...args);
    }, delay);
  };
};

Using wrapping function with debounce

// Define a function called 'searchData' that logs a message to the console
function searchData() {
  console.log("searchData executed");
}

// Create a new debounced version of the 'searchData' function with a delay of 3000 milliseconds (3 seconds)
const debouncedSearchData = debounce(searchData, 3000);

// Call the debounced version of 'searchData'
debouncedSearchData();

Now, whenever we call debouncedSearchData, it will not execute searchDataimmediately, but wait for 3 seconds.

If debouncedSearchData is called again within 3 seconds, it will reset the timer and wait for another 3 seconds.

Only when 3 seconds have passed without any new calls to debouncedSearchData, it will finally execute searchData.

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• When you click a submit button on a website, it doesn’t send the data right away. Instead, it waits for a brief moment to see if you might click it again. This prevents accidental double submissions and ensures that the data is only sent once, reducing errors and confusion.

• When you press the button to call the elevator, it doesn’t immediately move. The system waits for a few seconds to see if anyone else presses a button. This prevents the elevator from moving up and down unnecessarily, saving both time and energy.

• When typing in a search box, the suggestions don’t show up with every keystroke. Instead, the system waits until you stop typing for a moment before making the request. This minimizes unnecessary server calls and improves both performance and the user experience, especially for applications with large datasets.

In each of these cases, debouncing ensures that actions are only triggered when absolutely necessary, optimizing efficiency and reducing unnecessary operations.