## getIdentifier() function

Returns the resource identifier for the given system.

If multiple identifiers exist with the same system, the first one is returned.

If the system is not found, then returns undefined.

**Signature:**

```typescript
export declare function getIdentifier(resource: Resource, system: string): string | undefined;
```

## Parameters

| Parameter | Type | Description |
| --- | --- | --- |
| resource | Resource | The resource to check. |
| system | string | The identifier system. |

**Returns:**

string | undefined

The identifier value if found; otherwise undefined.