---
url: /process-functions/datasource-cacheexists.md
description: Checks whether a key is in the server-wide in-memory cache.
---

# datasource.cacheExists

Checks whether a key is in the server-wide in-memory cache.

```js
datasource.cacheExists(key)
```

## Parameters

| Parameter | Type | Description |
|---|---|---|
| `key` | `string` | The key. |

## Returns

`true` when the key is in the cache. `false` when it was never set or has expired.

## Examples

```js
if (!datasource.cacheExists("dailyRate")) {
    datasource.cacheSet("dailyRate", "1.52", 3600000);
}
```