# Function: isTrackedEnvelope()

> 

> **isTrackedEnvelope**\<`TData`\>(`value`): `value is TrackedEnvelope<TData>`

Defined in: [packages/server/src/unstable-core-do-not-import/stream/tracked.ts:30](https://github.com/trpc/trpc/blob/7c907acfd8b31929214792e3b8c2ad7a8ac72563/packages/server/src/unstable-core-do-not-import/stream/tracked.ts#L30)

Whether a value was made by `tracked()`.

## Type Parameters

| Type Parameter |
| ------ |
| `TData` |

## Parameters

| Parameter | Type |
| ------ | ------ |
| `value` | `unknown` |

## Returns

`value is TrackedEnvelope<TData>`