---
lang: en
title: 'API docs: testlab.createstubinstance'
keywords: LoopBack 4.0, LoopBack 4
sidebar: lb4_sidebar
permalink: /doc/en/lb4/apidocs.testlab.createstubinstance.html
---

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[Home](./index.md) &gt; [@loopback/testlab](./testlab.md) &gt; [createStubInstance](./testlab.createstubinstance.md)

## createStubInstance() function

Creates a new object with the given functions as the prototype and stubs all implemented functions.

Note: The given constructor function is not invoked. See also the stub API.

This is a helper method replacing `sinon.createStubInstance` and working around the limitations of TypeScript and Sinon, where Sinon is not able to list private/protected members in the type definition of the stub instance and therefore the stub instance cannot be assigned to places expecting TType. See also - https://github.com/Microsoft/TypeScript/issues/13543 - https://github.com/DefinitelyTyped/DefinitelyTyped/issues/14811

<b>Signature:</b>

```typescript
export declare function createStubInstance<TType>(constructor: sinon.StubbableType<TType>): StubbedInstanceWithSinonAccessor<TType>;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  constructor | <code>sinon.StubbableType&lt;TType&gt;</code> | Object or class to stub. |

<b>Returns:</b>

`StubbedInstanceWithSinonAccessor<TType>`

A stubbed version of the constructor, with an extra property `stubs` providing access to stub API for individual methods.


