How to Implement a Wait Function in JavaScript for Asynchronous Tasks?

Timing Delays in JavaScript

Understanding timing delays in JavaScript is crucial for building responsive and efficient web applications. In this article, we'll address the problem of waiting for a specific time before executing a line of code.

The Issue:

A novice JavaScript developer has encountered an issue where a function is not waiting as intended before evaluating a condition. The expected behavior is to wait for 5 seconds before checking if a certain state has changed. However, the current function checks immediately instead of waiting.

The Solution:

To achieve this desired behavior, we can utilize the following approaches:

Browser:

Using the modern async/await syntax (available in browsers that support ECMAScript 6 and above), we can employ the following solution:

<code class="javascript">const delay = ms => new Promise(res => setTimeout(res, ms));

async function yourFunction() {
  await delay(5000);
  console.log("Waited 5s");

  await delay(5000);
  console.log("Waited an additional 5s");
}</code>

This approach simplifies the code by making it appear synchronous, despite executing asynchronously.

Node.js:

For Node.js version 16 and above, we can leverage the built-in promise-based setTimeout function:

<code class="javascript">import { setTimeout } from "timers/promises";

async function yourFunction() {
  await setTimeout(5000);
  console.log("Waited 5s");

  await setTimeout(5000);
  console.log("Waited an additional 5s");
}</code>

Caution:

It's important to note that using a delay function to avoid race conditions (especially when testing asynchronous code) should be done with caution, as it can often lead to suboptimal solutions.

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