JavaScript typedArray.from() Property

The typedArray.from() is an inbuilt function in JavaScript which is used to construct a new typedArray from a normal array or any iterable object.

List of different typedArrays are specified in the table below:

Int8Array();	Int16Array();	Uint32Array();
Uint8Array();	Uint16Array();	Float32Array();
Uint8ClampedArray();	Int32Array();	Float64Array();

Syntax:

typedArray.from(source, mapFn, thisArg)

Parameters: It accepts three parameters which are specified below-

• source: It is a normal array or any iterable object for converting to a typedArray.
• mapFn: It is optional and it is map function to call on every element of the typedArray.
• thisArg: It is optional and it is the value to be used while executing mapFn function.

Return value: It returns a new typedArray instance. 

Example 1:

javascript

// Constructing an iterable object
var a = new Set([ 5, 10, 15, 20, 25 ]);
var b = new Set([ 1, 2, 3, 4, 5 ]);
var c = new Set([ 1, 3, 5, 7, 9 ]);
var d = new Set([ 2, 4, 6, 8, 10 ]);

// Calling from() function
A = Uint8Array.from(a);
B = Uint8Array.from(b);
C = Uint8Array.from(c);
D = Uint8Array.from(d);

// Printing new typedArray instance
console.log(A);
console.log(B);
console.log(C);
console.log(D);

Output:

5, 10, 15, 20, 25
1, 2, 3, 4, 5
1, 3, 5, 7, 9
2, 4, 6, 8, 10

Example 2:

javascript

// Calling from() function
A = Uint16Array.from('123456');
B = Uint16Array.from('80397418327');

// Printing new typedArray instance
console.log(A);
console.log(B);

Output:

1, 2, 3, 4, 5, 6
8, 0, 3, 9, 7, 4, 1, 8, 3, 2, 7

Example 3:

javascript

// Constructing an iterable object
var a = new Set([ 5, 10, 15, 20, 25 ]);
var b = new Set([ 1, 2, 3, 4, 5 ]);
var c = new Set([ 1, 3, 5, 7, 9 ]);
var d = new Set([ 2, 4, 6, 8, 10 ]);

// Calling from() function
A = Uint8Array.from(a, x => x + 1);
B = Uint8Array.from(b, x => x + 2);
C = Uint8Array.from(c, x => x * 2);
D = Uint8Array.from(d);

// Printing new typedArray instance
console.log(A);
console.log(B);
console.log(C);
console.log(D);

Output:

6, 11, 16, 21, 26
3, 4, 5, 6, 7
2, 6, 10, 14, 18
2, 4, 6, 8, 10