---
url: /process-functions/mapping-exists.md
description: Returns true or false if the mapping exists or does not.
---

# mapping.exists

Returns `true` or `false` if the mapping exists or does not.

```js
mapping.exists(mappingName);
```

#### Parameters

* `mappingName` - An identifier used to find the target mapping.

#### Example

```js
if(mapping.exists("Time to Year and Month")) { 
    //it exists
}
```

:::tip
If a mapping exists with this name the code inside the if statement will run, otherwise it will be skipped.
:::