# Interface: Observer<TValue, TError>

> 

Defined in: [packages/server/src/observable/types.ts:62](https://github.com/trpc/trpc/blob/7c907acfd8b31929214792e3b8c2ad7a8ac72563/packages/server/src/observable/types.ts#L62)

Gets an observable's values, its error, and its end.

## Type Parameters

| Type Parameter |
| ------ |
| `TValue` |
| `TError` |

## Properties

### complete()

> **complete**: () => `void`

Defined in: [packages/server/src/observable/types.ts:68](https://github.com/trpc/trpc/blob/7c907acfd8b31929214792e3b8c2ad7a8ac72563/packages/server/src/observable/types.ts#L68)

Called when the observable ends without an error.

#### Returns

`void`

***

### error()

> **error**: (`err`) => `void`

Defined in: [packages/server/src/observable/types.ts:66](https://github.com/trpc/trpc/blob/7c907acfd8b31929214792e3b8c2ad7a8ac72563/packages/server/src/observable/types.ts#L66)

Gets the error the observable ends with.

#### Parameters

| Parameter | Type |
| ------ | ------ |
| `err` | `TError` |

#### Returns

`void`

***

### next()

> **next**: (`value`) => `void`

Defined in: [packages/server/src/observable/types.ts:64](https://github.com/trpc/trpc/blob/7c907acfd8b31929214792e3b8c2ad7a8ac72563/packages/server/src/observable/types.ts#L64)

Gets each value.

#### Parameters

| Parameter | Type |
| ------ | ------ |
| `value` | `TValue` |

#### Returns

`void`