search
HomeWeb Front-endJS TutorialHow to convert JavaScript iterator to array?

如何将 JavaScript 迭代器转换为数组?

In JavaScript, an iterator is a collection of elements through which we can iterate and access a single element in each iteration. Collections, maps or objects are iterators in JavaScript and we cannot access the elements of iterators using indexes like we can with arrays.

So, we first need to convert the iterator to an array. Here we will convert iterator to array using different methods like array.from() etc.

Use for-of loop

for-of loops over each element of the iterator lies collection and map. In the for-of loop we can access and add elements to the array and we can use push() method to add elements to the array.

grammar

Users can use the for-of loop to convert the iterator into an array according to the following syntax.

for (let element of iterator) {
   array.push(element);
}

In the above syntax, we access the elements of the iterator in the for-of loop and push it to the array

Example 1

In the example below, we create test_array and initialize it with some numbers. After that, we use Symbol.iterator() to convert the array into an iterator.

Next, we use a for-of loop to iterate over the iterator. We access all the elements of the iterator one by one and push them into the array. Once all iterations of the for loop are completed, we get the complete array of iterators.

<html>
<body>
   <h2 id="Using-the-i-for-loop-i-to-transform-JavaScript-iterator-into-the-array">Using the <i> for loop </i> to transform JavaScript iterator into the array</h2> 
   <div id = "output"> </div>
</body>
<script>
   let output = document.getElementById('output');
   let test_array = [10, 20, 30, 0, 50, 60, 70];
   let iterator = test_array[Symbol.iterator]();
   let array = [];
   for (let element of iterator) {
      array.push(element);
      output.innerHTML += "Array element is - " + element + "<br>";
   }
   output.innerHTML += "The whole array is - " + array;
</script>
</html>

Use array.from() method

The Array.from() method creates an array from an iterator. We need to pass the iterator object as parameter of array.from() method. After converting the iterator to an array, it returns an array.

grammar

Users can use the array.from() method according to the following syntax to convert the iterator to an array.

let array = Array.from(test_set); 

In the above syntax, test_set is an iterator to be converted to an array.

parameter

test_set – It is an iterator to be converted to an array.

Example 2

In the example below, we create a collection using various elements. After that, we convert the collection into an array using the array.from() method. In the output, the user can see the array returned from the array.from() method.

<html>
<body>
   <h2 id="Using-the-i-Array-from-method-i-to-transform-JavaScript-iterator-into-the-array">Using the <i> Array.from() method </i> to transform JavaScript iterator into the array.</h2>
   <div id = "output"> </div>
</body>
<script>
   let output = document.getElementById('output');
   let test_set = new Set(["Hello", "Hello", "Hi", 10, 10, 20, 30, 40, 40, true, false, true, true]);
   let array = Array.from(test_set);
   output.innerHTML += "The array from the test_set is " + array;
</script>
</html>

Use spread operator

The spread operator also allows us to convert iterators to arrays like the array.from() method. It copies all elements of the iterator into a new array. Additionally, we can use it to clone arrays.

grammar

Users can use the spread operator to convert the iterator into an array according to the following syntax

let array = [...test_map]; 

In the above syntax, test_map is an iterator.

Example 3

In the example below, we create a map with unique keys and values. We can access specific values ​​from the map using keys.

We have used the spread operator to convert test_map to an array. In the output, the user can see that each key and value of the map has been added to the array

<html>
<body>
   <h2 id="Using-the-i-Spread-operator-i-to-transform-JavaScript-iterator-into-the-array">Using the <i> Spread operator </i> to transform JavaScript iterator into the array.</h2>
   <div id = "output"> </div>
</body>
<script>
   let output = document.getElementById('output');
   var test_map = new Map([["first", true], ["second", false], ["third", false], ["fourth", true]]);
   let array = [...test_map]; 
   output.innerHTML += "The array from the test_map is " + array;
</script>
</html>

Example 4

In this example, we convert the collection iterator to an array. The new Set() constructor is used to create sets from numeric, boolean and string elements.

After that, we use the spread operator to convert the collection iterator into an array.

<html>
<body>
   <h2 id="Using-the-i-Spread-operator-i-to-transform-JavaScript-iterator-into-the-array">Using the <i> Spread operator </i> to transform JavaScript iterator into the array.</h2>
   <div id="output"> </div>
</body>
<script>
   let output = document.getElementById('output');
   let set = new Set([30, 40, "TypeScript", "JavaScript"])
   let array = [...set]
   output.innerHTML += "The array from the object is " + array;
</script>
</html>

In this tutorial, we looked at three different ways to convert an iterator into an array. The best way is to use the spread operator as it also provides another functionality like cloning an array.

The above is the detailed content of How to convert JavaScript iterator to array?. 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

Custom Google Search API Setup TutorialCustom Google Search API Setup TutorialMar 04, 2025 am 01:06 AM

This tutorial shows you how to integrate a custom Google Search API into your blog or website, offering a more refined search experience than standard WordPress theme search functions. It's surprisingly easy! You'll be able to restrict searches to y

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

Example Colors JSON FileExample Colors JSON FileMar 03, 2025 am 12:35 AM

This article series was rewritten in mid 2017 with up-to-date information and fresh examples. In this JSON example, we will look at how we can store simple values in a file using JSON format. Using the key-value pair notation, we can store any kind

8 Stunning jQuery Page Layout Plugins8 Stunning jQuery Page Layout PluginsMar 06, 2025 am 12:48 AM

Leverage jQuery for Effortless Web Page Layouts: 8 Essential Plugins jQuery simplifies web page layout significantly. This article highlights eight powerful jQuery plugins that streamline the process, particularly useful for manual website creation

What is 'this' in JavaScript?What is 'this' in JavaScript?Mar 04, 2025 am 01:15 AM

Core points This in JavaScript usually refers to an object that "owns" the method, but it depends on how the function is called. When there is no current object, this refers to the global object. In a web browser, it is represented by window. When calling a function, this maintains the global object; but when calling an object constructor or any of its methods, this refers to an instance of the object. You can change the context of this using methods such as call(), apply(), and bind(). These methods call the function using the given this value and parameters. JavaScript is an excellent programming language. A few years ago, this sentence was

Improve Your jQuery Knowledge with the Source ViewerImprove Your jQuery Knowledge with the Source ViewerMar 05, 2025 am 12:54 AM

jQuery is a great JavaScript framework. However, as with any library, sometimes it’s necessary to get under the hood to discover what’s going on. Perhaps it’s because you’re tracing a bug or are just curious about how jQuery achieves a particular UI

10 Mobile Cheat Sheets for Mobile Development10 Mobile Cheat Sheets for Mobile DevelopmentMar 05, 2025 am 12:43 AM

This post compiles helpful cheat sheets, reference guides, quick recipes, and code snippets for Android, Blackberry, and iPhone app development. No developer should be without them! Touch Gesture Reference Guide (PDF) A valuable resource for desig

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
Repo: How To Revive Teammates
1 months agoBy尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

EditPlus Chinese cracked version

EditPlus Chinese cracked version

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

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

VSCode Windows 64-bit Download

VSCode Windows 64-bit Download

A free and powerful IDE editor launched by Microsoft