---
lang: en
title: 'API docs: testlab.createstubinstance'
keywords: LoopBack 4.0, LoopBack 4, Node.js, TypeScript, OpenAPI
sidebar: lb4_sidebar
editurl: https://github.com/loopbackio/loopback-next/tree/master/packages/testlab
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

**Signature:**

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

## Parameters

<table><thead><tr><th>

Parameter


</th><th>

Type


</th><th>

Description


</th></tr></thead>
<tbody><tr><td markdown="1">

constructor


</td><td markdown="1">

sinon.StubbableType&lt;TType&gt;


</td><td markdown="1">

Object or class to stub.


</td></tr>
</tbody></table>

**Returns:**

[StubbedInstanceWithSinonAccessor](./testlab.stubbedinstancewithsinonaccessor.md)<!-- -->&lt;TType&gt;

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