`String.prototype.lastIndexOf()`

Returns the index of the last occurrence of a substring, or -1 if absent.

Syntax

str.lastIndexOf(searchString, position)

Name	Type	Required	Description
`searchString`	`string`	Yes	The substring to search for.
`position`	`number`	No	The index at or before which to search, scanning backwards. Defaults to +Infinity.

number — The index of the last match, or -1 if not found.

console.log('abcabc'.lastIndexOf('b'));

Output

console.log('abc'.lastIndexOf('z'));

Output

-1

Case-sensitive. The match itself must start at or before `position`. Returns the absolute forward index of the match.