JavaScript (ES2026) reference · Array Methods

JavaScript Array lastIndexOf() Method

Return the last index at which a value is found (using ===), searching backwards, or -1 if it isn't there.

JavaScript (ES2026) Since ES5

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Syntax

array.lastIndexOf(searchElement, fromIndex)

Parameter	Description
`searchElement`	The value to look for.
`fromIndex` optional	Index to start searching backwards from.

An index, or -1.

Last occurrenceTry it yourself

const nums = [2, 5, 9, 2];
console.log(nums.lastIndexOf(2), nums.lastIndexOf(7));

Output

3 -1

Search before a positionTry it yourself

const path = ["home", "user", "docs", "user"];
console.log(path.lastIndexOf("user", 2));

Output

Version	Change
JavaScript ES5	Added

array.indexOf() · Return the first index at which a value is found (using ===), or -1 if it isn't in the array.
array.findLastIndex() · Return the index of the last element that passes a test function, or -1 if none does.
JavaScript Arrays · tutorial
JavaScript Array Methods · tutorial