How to use the codePointAt method in JavaScript

by Janeth Kent Date: 23-07-2021 javascript


The JavaScript codePointAt method has more or less the same function as the charCodeAt method, used to get the 16-bit Unicode representation of the character at a certain position in a string.

However, certain characters present a small problem, as they use two 16-bit units, so the charCodeAt method will only return half of the representation of these special characters.

The codePointAt method was introduced in JavaScript in its ES2015 version in order to get Unicode representations of characters that use two 16-bit units instead of just one. In general, you can get all Latin or Saxon characters using the charCodeAt method, but not Chinese or Japanese characters. The codePointAt method accepts as a parameter the index of the string to which the method is applied, which may be a standard string declared with single or double quotes, a String object or a template literal

The value returned by the codePointAt method will be undefined when the index we pass to the method has no representation.

For example, to get the Unicode representation in decimal or hexadecimal formed by two Unicode UTF-16 units of the character Unicode UTF-16 we would have to use the charCodeAt method twice:

 
// Decimal representation  
const firstPart = 'Unicode UTF-16'.charCodeAt(0); // 55362  
const secondPart= 'Unicode UTF-16'.charCodeAt(1); // 57271    
// Hexadecimal representation  
const firstPart = 'Unicode UTF-16'.charCodeAt(0).toString(16); // d842  
const secondPart = 'Unicode UTF-16'.charCodeAt(1).toString(16); // dfb7
 

You can see that if you put both parts together and show them through the console, you get the character Unicode UTF-16:

 
console.log('ud842udfb7'); // Unicode UTF-16
 

However, it is possible to obtain the character representation using the codePointAt method only once:

 
// Decimal representation  
const decimal = 'Unicode UTF-16'.codePointAt>(0); // 134071    
// Hexadecimal representation  
const hexadecimal = 'Unicode UTF-16'.codePointAt(0).toString(16); // 20bb7
 

To check that the result is correct, simply display the result via the console:

 
console.log('u{20bb7}');
 

If you use a String object, the process is exactly the same:

 
const mychain = new String('Unicode UTF-16'); 
    
// Decimal representation  
const decimal = mychain.codePointAt(0); // 134071 
   
// Hexadecimal representation  
const hexadecimal = mychain.codePointAt(0).toString(16); // 20bb7

 
by Janeth Kent Date: 23-07-2021 javascript hits : 8374  
 
Janeth Kent

Janeth Kent

Licenciada en Bellas Artes y programadora por pasión. Cuando tengo un rato retoco fotos, edito vídeos y diseño cosas. El resto del tiempo escribo en MA-NO WEB DESIGN END DEVELOPMENT.

 
 
 

Related Posts

How to create PDF with JavaScript and jsPDF

Creating dynamic PDF files directly in the browser is possible thanks to the jsPDF JavaScript library. In the last part of this article we have prepared a practical tutorial where I…

How to make your own custom cursor for your website

When I started browsing different and original websites to learn from them, one of the first things that caught my attention was that some of them had their own cursors,…

Node.js and npm: introductory tutorial

In this tutorial we will see how to install and use both Node.js and the npm package manager. In addition, we will also create a small sample application. If you…

How to connect to MySQL with Node.js

Let's see how you can connect to a MySQL database using Node.js, the popular JavaScript runtime environment. Before we start, it is important to note that you must have Node.js installed…

JavaScript Programming Styles: Best Practices

When programming with JavaScript there are certain conventions that you should apply, especially when working in a team environment. In fact, it is common to have meetings to discuss standards…

Difference between arrow and normal functions in JavaScript

In this tutorial we are going to see how arrow functions differ from normal JavaScript functions. We will also see when you should use one and when you should use…

JavaScript Arrow functions: What they are and how to use them

In this article we are going to see what they are and how to use JavaScript Arrow Functions, a new feature introduced with the ES6 standard (ECMAScript 6). What are Arrow…

How to insert an element into an array with JavaScript

In this brief tutorial you will learn how to insert one or more elements into an array with JavaScript. For this we will use the splice function. The splice function will not…

What is the difference between primitives types and objects in JavaScript?

In this short tutorial we are going to look at the differences between primitive types and objects in JavaScript. To start with, we're going to look at what primitive types…

How to get DOM elements with JavaScript

When you access any element of the DOM, it is usual to save it in a variable. This is something that at first might seem very simple, but if you…

How to reverse an array in JavaScript

In this tutorial we are going to see how you can change the order of the elements of an array so that they are inverted. You could use a loop…

How synchronize the scroll of two divs with JavaScript

In case you have two divs of different sizes you may sometimes want to scroll both at the same time but at different speeds depending on their size. For example,…

We use our own and third-party cookies to improve our services, compile statistical information and analyze your browsing habits. This allows us to personalize the content we offer and to show you advertisements related to your preferences. By clicking "Accept all" you agree to the storage of cookies on your device to improve website navigation, analyse traffic and assist our marketing activities. You can also select "System Cookies Only" to accept only the cookies required for the website to function, or you can select the cookies you wish to activate by clicking on "settings".

Accept All Only sistem cookies Configuration