array.indexOf()

Get the index of the first Array element that matches a provided value.

Signature

indexOf(element: A) => Number | Null

indexOf(element: A, start: Number) => Number | Null

Description

Searches, left-to-right, for the first element that matches a provided value and returns the index of the element if a match is found.

If an optional start index is provided, the method searches left-to-right starting at the start index and returns the first matching index (inclusive).

Parameters

Parameter Type Required Description

element

Generic

true

Value to search for in the Array elements.

start

Number

Starting index (inclusive) of the left-to-right search. Must be an Int.

Return value

One of:

Type Description

Number

Index of the element that matches the provided value.

Null

Returned if a match isn’t found.

Examples

['a', 'b', 'c', 'b'].indexOf('c')
2
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