search
HomeWeb Front-endJS TutorialHow to wrap setTimeout() method in Promise?

如何将 setTimeout() 方法包装在 Promise 中?

The setTimeOut() method executes some code or function after a specific number of milliseconds. Sometimes, we need to resolve or reject a promise after a specific delay, we can use the setTimeout() method with the promise.

In JavaScript, promise is an object that returns the result of an asynchronous operation. Here we will learn to use the setTimeOut() method to resolve or reject a promise after a delay.

Example 1 (Promise without setTimeOut() method)

In the following example, we use the Promise() constructor to create a new Promise. The Promise constructor accepts a callback function as a parameter, and the callback function executes the resolve() method to resolve the Promise. It demonstrates the basic usage of Promise.

<html>
<body>
   <h2 id="Using-the-Promises-without-setTimeOut-method-in-JavaScript">Using the Promises without setTimeOut() method in JavaScript</h2>
   <div id = "content"> </div> <br />
   <button onclick = "start()"> Resolve Promise </button>
   <script>
      let content = document.getElementById('content');
      
      // function for promise example
      function start() {
         let promise = new Promise(function (resolve, reject) {
            resolve("Promise is resolved!");
         });
         promise.then((value) => {
            content.innerHTML = "The result from resolved promise is " + value;
         });
      } 
   </script>
</body>
</html>

grammar

Users can use the setTimeOut() method with Promise according to the following syntax.

new Promise(function (resolve, reject) {
   setTimeout(function () {
      resolve();
   }, delay);
}); 

In the above syntax, we execute the resolve() method in the setTimeOut() method. It executes the resolve() method after a "delay" of milliseconds.

Example 2 (Promise with async function and setTimeOut() method)

In the example below, we create an asynchronous function named "resolvePromise". We create the Promise and store it in the "sumPromise" variable. After we use the await keyword to suspend function execution until the promise is resolved.

The user can observe in the output that whenever they press the button, it resolves the promise after 2000 milliseconds.

<html>
<body>
   <h3 id="Using-Promises-with-setTimeOut-method-and-async-functions-in-JavaScript">Using Promises with setTimeOut() method and async functions in JavaScript</h3>
   <div id = "content"> </div> <br>
   <button onclick = "resolvePromise()"> Resolve Promise </button>
   <script>
      let content = document.getElementById('content');
      
      // function for promise example
      async function resolvePromise() {
         let sumPromise = new Promise(function (resolve, reject) {
            setTimeout(function () {
               resolve("The sum of all data is 100.");
            }, 3000);
         });
         let result = await sumPromise;
         content.innerHTML = "The resolved promise's result is " + result;
      }
   </script>
</body>
</html>

Example 3 (Promise with then() block and setTimeout() method)

In the following example, we use a then() block to resolve the Promise instead of using async/await syntax, as shown in Example 2. We also use setTimeOut() in a Promise, as shown in Example 2, to resolve the promise after a delay.

<html>
<body>
   <h2 id="Using-the-Promises-with-setTimeOut-method-in-JavaScript">Using the Promises with setTimeOut() method in JavaScript</h2>
   <div id = "content"></div>
   <br>
   <button onclick = "resolvePromise()"> Resolve Promise </button>
   <script>
      let content = document.getElementById('content');
      
      // function for promise example
      function resolvePromise() {
         let promise = new Promise(function (resolve, reject) {
            setTimeout(function () {
               resolve("This promise is resolved after 2000 milliseconds");
            }, 2000);
         });
         promise.then(function (value) {
            content.innerHTML = "The resolved promise's result is " + value;
         });
      }
   </script>
</body>
</html>

This tutorial teaches users to wrap the setTimeOut() method in Promise. Additionally, we use async/await syntax and then() blocks to resolve Promise. Users can observe the output of the above example, which resolves the promise after a specific millisecond.

The above is the detailed content of How to wrap setTimeout() method in Promise?. For more information, please follow other related articles on the PHP Chinese website!

Statement
This article is reproduced at:tutorialspoint. If there is any infringement, please contact admin@php.cn delete
Replace String Characters in JavaScriptReplace String Characters in JavaScriptMar 11, 2025 am 12:07 AM

Detailed explanation of JavaScript string replacement method and FAQ This article will explore two ways to replace string characters in JavaScript: internal JavaScript code and internal HTML for web pages. Replace string inside JavaScript code The most direct way is to use the replace() method: str = str.replace("find","replace"); This method replaces only the first match. To replace all matches, use a regular expression and add the global flag g: str = str.replace(/fi

Build Your Own AJAX Web ApplicationsBuild Your Own AJAX Web ApplicationsMar 09, 2025 am 12:11 AM

So here you are, ready to learn all about this thing called AJAX. But, what exactly is it? The term AJAX refers to a loose grouping of technologies that are used to create dynamic, interactive web content. The term AJAX, originally coined by Jesse J

10 jQuery Fun and Games Plugins10 jQuery Fun and Games PluginsMar 08, 2025 am 12:42 AM

10 fun jQuery game plugins to make your website more attractive and enhance user stickiness! While Flash is still the best software for developing casual web games, jQuery can also create surprising effects, and while not comparable to pure action Flash games, in some cases you can also have unexpected fun in your browser. jQuery tic toe game The "Hello world" of game programming now has a jQuery version. Source code jQuery Crazy Word Composition Game This is a fill-in-the-blank game, and it can produce some weird results due to not knowing the context of the word. Source code jQuery mine sweeping game

How do I create and publish my own JavaScript libraries?How do I create and publish my own JavaScript libraries?Mar 18, 2025 pm 03:12 PM

Article discusses creating, publishing, and maintaining JavaScript libraries, focusing on planning, development, testing, documentation, and promotion strategies.

jQuery Parallax Tutorial - Animated Header BackgroundjQuery Parallax Tutorial - Animated Header BackgroundMar 08, 2025 am 12:39 AM

This tutorial demonstrates how to create a captivating parallax background effect using jQuery. We'll build a header banner with layered images that create a stunning visual depth. The updated plugin works with jQuery 1.6.4 and later. Download the

How do I optimize JavaScript code for performance in the browser?How do I optimize JavaScript code for performance in the browser?Mar 18, 2025 pm 03:14 PM

The article discusses strategies for optimizing JavaScript performance in browsers, focusing on reducing execution time and minimizing impact on page load speed.

Auto Refresh Div Content Using jQuery and AJAXAuto Refresh Div Content Using jQuery and AJAXMar 08, 2025 am 12:58 AM

This article demonstrates how to automatically refresh a div's content every 5 seconds using jQuery and AJAX. The example fetches and displays the latest blog posts from an RSS feed, along with the last refresh timestamp. A loading image is optiona

Getting Started With Matter.js: IntroductionGetting Started With Matter.js: IntroductionMar 08, 2025 am 12:53 AM

Matter.js is a 2D rigid body physics engine written in JavaScript. This library can help you easily simulate 2D physics in your browser. It provides many features, such as the ability to create rigid bodies and assign physical properties such as mass, area, or density. You can also simulate different types of collisions and forces, such as gravity friction. Matter.js supports all mainstream browsers. Additionally, it is suitable for mobile devices as it detects touches and is responsive. All of these features make it worth your time to learn how to use the engine, as this makes it easy to create a physics-based 2D game or simulation. In this tutorial, I will cover the basics of this library, including its installation and usage, and provide a

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Best Graphic Settings
2 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. How to Fix Audio if You Can't Hear Anyone
2 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

VSCode Windows 64-bit Download

VSCode Windows 64-bit Download

A free and powerful IDE editor launched by Microsoft

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

EditPlus Chinese cracked version

EditPlus Chinese cracked version

Small size, syntax highlighting, does not support code prompt function

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

mPDF

mPDF

mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),