Node.js TextEncoder

The TextEncoder is an interface that takes a stream of code points as input and emits a stream of encoded UTF-8 codes. This is provided in NodeJS as an implementation of the WHATWG Encoding Standard ‘TextEncoder’ API. All instances of TextEncoder only support UTF-8 encoding.

UTF-8: It is an encoding mechanism that encodes in multiple 8 bits. It is capable of encoding all 1,112,064 characters in 4 bytes, each of 8 bits. The first 128 characters match the ASCII mapping.

Import:

var util = require('util');

Syntax:

util.TextEncoder( );

Constructor:

• TextEncoder( ): This method will return an new object of TextEncoder class which can generated encoding of UTF-8 format.

Properties:

The TextEncoder class does not inherit any property. Only one property is defined which is:

• TextEncoder.prototype.encoding: It is a read-only property that returns a string of the name of the encoding used by the object. It always returns UTF-8.

Functions:

• encode(string): returns Uint8Array from a ‘string’.
• encodeInto(string, dest): takes two parameters Input first is the input string and the second is the output array. It encodes ‘string’ into ‘dest’ that must be Uint8Array.

Return Value: Returns an array corresponding to encoding format containing code points representing input.

Example 1: We will encode and save the output in a local variable and print it on the console to check the encoded value. Create a file index.js and write the below code:

Javascript

var util = require('util');
let encoder = new util.TextEncoder();
let uint8Array = encoder.encode("Hello");
console.log(uint8Array);

Steps to run the application: Write the below command in the terminal to start the server:

node index.js

Output:

Uint8Array [ 72, 101, 108, 108, 111 ]

Example 2: We will now encode the string into an output array bigger than the size of the input to see how they function encodes. Create a file index.js and write the below code:

Javascript

var util = require('util');
let encoder = new util.TextEncoder();
let src = "Hello";
let uint8Array = new Uint8Array(10);
encoder.encodeInto(src, uint8Array);
console.log(uint8Array);

Steps to run the application: Write the below command in the terminal to start the server:

node index.js

Output:

Uint8Array(10) [ 72, 101, 108, 108, 111,0,   0,   0,   0,   0]

Browser Compatibility:

BROWSER	VERSION SUPPORTED
Chrome	38
Edge	79
Firefox	18
Internet Explorer	NOT SUPPORTED
Opera	25
Safari	10.1
Android WebView	38
Deno	1.0
NodeJS	8.3.0
Samsung Internet	3.0
Safari iOS	10.3

Reference: https://nodejs.org/api/util.html#class-utiltextencoder