# Array.find_index

## Function

Returns the index of the first element for which the callback result is true.

## Syntax

```bt
array.find_index(callback)
```

## Parameters

| Parameters | Type | Required | Default value | Description |
| ------ | ------ | ------ | ------ | ------ |
| callback | Fn | No | Empty | The callback signature is fn(value, index, current). |

## Return value

| Type | Description |
| ------ | ------ |
| Int | Returns the subscript if found; returns -1 if not found. |

## Example

```bt
items = [1, 2, 3]
result = items.find_index(fn(value) { value > 1 })

// Output: 1
print result
```

## Notes

- Search from left to right.