typedArray.indexOf

The indexOf() method returns the first index at which a given element can be found in the typed array, or -1 if it is not present. This method has the same algorithm as Array.prototype.indexOf(). TypedArray is one of the typed array types here.

Syntax

typedarray.indexOf(searchElement[, fromIndex = 0])

Parameters

searchElement

Element to locate in the typed array.

fromIndex

The index to start the search at. If the index is greater than or equal to the typed array's length, -1 is returned, which means the typed array will not be searched. If the provided index value is a negative number, it is taken as the offset from the end of the typed array. Note: if the provided index is negative, the typed array is still searched from front to back. If the calculated index is less than 0, then the whole typed array will be searched. Default: 0 (entire typed array is searched).

Return value

The first index of the element in the array; -1 if not found.

Description

indexOf compares searchElement to elements of the typed array using strict equality (the same method used by the ===, or triple-equals, operator).

Examples

var uint8 = new Uint8Array([2, 5, 9]);
uint8.indexOf(2);     // 0
uint8.indexOf(7);     // -1
uint8.indexOf(9, 2);  // 2
uint8.indexOf(2, -1); // -1
uint8.indexOf(2, -3); // 0

Specifications

Specification	Status	Comment
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'TypedArray.prototype.indexOf' in that specification.	Standard	Initial definition.
ECMAScript 2017 Draft (ECMA-262) The definition of 'TypedArray.prototype.indexOf' in that specification.	Draft

Browser compatibility

Compatibility notes

• Starting with Firefox 47 (Firefox 47 / Thunderbird 47 / SeaMonkey 2.44), this method will no longer return -0.
  For example, new Uint8Array([0]).indexOf(0, -0) will now always return +0 (bug 1242043).

See also

• TypedArray.prototype.lastIndexOf()
• Array.prototype.indexOf()