> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.itential.com/itential-platform/6/studio/tasks/reference/array-index-of/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.itential.com/_mcp/server.

# arrayIndexOf

> Use the indexOf task to find the first index position of an element in an array.

The `arrayIndexOf` task returns the first index (position) at which a given element can be found in the array. The task returns `-1` if the element is not found.

## Potential use case

Suppose you have a list of email addresses and want to determine if an email record is listed in the correct department. The `arrayIndexOf` task checks whether the email exists and returns the index position where it occurs. If the email is not found, it returns `-1`.

## Properties

| Incoming        | Type   | Description                                                        |
| :-------------- | :----- | :----------------------------------------------------------------- |
| `arr`           | Array  | Required. The array to search.                                     |
| `searchElement` | Any    | Required. The element to search for.                               |
| `fromIndex`     | Number | Optional. The index position to start the search. Defaults to `0`. |

| Outgoing | Type   | Description                                                      |
| :------- | :----- | :--------------------------------------------------------------- |
| `index`  | Number | The position of the element in `arr`. Returns `-1` if not found. |

## Example

In this example:

* The `arr` variable is statically set to `["Apple","Pear","Banana"]`.
* The `searchElement` is `Banana`.
* The `fromIndex` defaults to `0`.
* The `index` result returns `2`, indicating that `Banana` is at index position two in the array.

Array indexing is zero-based: the first element is at position `0`, the second at `1`, and so on.

![](/_fern-img/73d080ea269c2df0eddc14d9e4ef8dde8a55f6900858ee0f2bb7534176cb3bfb.webp)

> Use the indexOf task to find the first index position of an element in an array.