> ## Documentation Index
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> Use this file to discover all available pages before exploring further.

# findIndex

> Finds the index of a given element in an array.

## Signature

```typescript path=null start=null theme={null}
findIndex<T>(arr: T[], element: T): number
```

## Type Parameters

* **T**

## Parameters

* **arr**: `T[]` - The array in which to find the element.
* **element**: `T` - The element to find.

## Returns

`number` - The index of the element in the array, or -1 if the element is not found.

## Example

```typescript path=null start=null theme={null}
const arr = [1, 2, 3, 4, 5]
const element = 3
const index = findIndex(arr, element)
console.log(index) // 2
```

## Source

Defined in [array.ts:53](https://github.com/koji/ichigyou/blob/main/src/array.ts#L53)