# Array join

Returns a new string by concatenating all of the elements in an array, separated by commas or a specified separator string. Array join lives in the **Array** category of the `fx` menu.

## Parameters

| Parameter | Type   | Required | Default | Description                                            |
| --------- | ------ | -------- | ------- | ------------------------------------------------------ |
| Input     | string | yes      | —       | Value to transform. Previous step output or a literal. |
| Separator | string | no       | `,`     | A separator to use in the join operation               |

`Input` is the primary value (previous step output or a literal).

## Returned value

| Type     | Description                              |
| -------- | ---------------------------------------- |
| `string` | Result of the Array join transformation. |

## Limitations

- Array arguments must be valid JSON arrays. Invalid JSON or non-array values raise an error.

## Example

<details>
<summary>Run Array join</summary>

Returns a new string by concatenating all of the elements in an array, separated by commas or a specified separator string Adjust optional parameters when the defaults do not match your payload.

1. Set **Input** to the value to transform (previous step output or a literal).

2. Review **Separator** and keep defaults unless your format requires otherwise.

3. Confirm **Output value** shows the transformed result.

</details>