JavaScript typedArray.lastIndexOf() Method

The typedArray.lastIndexOf() is an inbuilt function in JavaScript which is used to return the last index of the typedArray at which a given element is present otherwise it returns -1 if the element is not present. 

Syntax:

typedArray.lastIndexOf(search_Element, from_Index])

Parameters: It accepts two parameters which are specified below:

• search_Element: It is the element whose last index is to be searched.
• from_Index: It is optional. It is the index up to which an element is to be searched and its default value is the length of the typedArray.

Return value: It returns the last index of the typedArray at which a given element is present otherwise it returns -1 if the element is not present.

Example 1:

javascript

// Creating a typedArray with some elements
var A = new Uint8Array([5, 10, 15, 15, 5, 20, 10]);

// Calling lastIndexOf() function
b = A.lastIndexOf(10);
c = A.lastIndexOf(5);
d = A.lastIndexOf(15);
e = A.lastIndexOf();
f = A.lastIndexOf(20);
g = A.lastIndexOf(25);

// Printing returned values
console.log(b);
console.log(c);
console.log(d);
console.log(e);
console.log(f);
console.log(g);

Output:

6
4
3
-1
5
-1

Example 2:

javascript

// Creating a typedArray with some elements
var A = new Uint8Array([5, 10, 15, 15, 5, 20, 10]);

// Calling lastIndexOf() function
b = A.lastIndexOf(10, 1);
c = A.lastIndexOf(5, 2);
d = A.lastIndexOf(15, 3);
e = A.lastIndexOf(15, 1);
f = A.lastIndexOf(20, 1);
g = A.lastIndexOf(25, 3);

// Printing returned values
console.log(b);
console.log(c);
console.log(d);
console.log(e);
console.log(f);
console.log(g);

Output:

1
0
3
-1
-1
-1