JavaScript Uint8Array.from() Method

The Uint8Array array represents an array of 8-bit unsigned integers. By default, the contents of Uint8Array are initialized to 0. The Uint8Array.from() method is used to create a new Uint8Array from an array-like or iterable object. So when you want to convert an arrayLike or iterable object then you can be used this function by passing the object as a parameter to this function along with the map function and value used for the map function if needed. 

Syntax: 

Uint8Array.from( source, mapFn, thisArg )

Parameters:

This method accepts three parameters as mentioned above and described below:

• source: This parameter contains an array-like or iterable object which is used to convert to a Uint8Array object.
• mapFn: It is an optional parameter which is the Map function to call on every element of the Uint8Array array.
• thisArg: It is an optional parameter that stores the value to use as this when executing mapFn.

Return Value:

This method returns a new Uint8Array instance. 

Below example illustrate the working of Uint8Array.from() method in JavaScript: 

Example 1: In this example, we will see the basic functionality of the Uint8Array array to create new Uint8array from a string of integers.

Uint8Array(17) [
  4, 5, 4, 6, 5, 7, 6,
  8, 6, 5, 4, 3, 2, 3,
  4, 5, 6
]

Example 2: In this example, we will see the basic functionality of the Uint8Array array to create a new Unit8array performing the required transformations.

Uint8Array(6) [ 4, 5, 6, 7, 8, 9 ]