---
lang: en
title: 'API docs: filter.isfilter'
keywords: LoopBack 4.0, LoopBack 4, Node.js, TypeScript, OpenAPI
sidebar: lb4_sidebar
editurl: https://github.com/loopbackio/loopback-next/tree/master/packages/filter
permalink: /doc/en/lb4/apidocs.filter.isfilter.html
---

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[Home](./index.md) &gt; [@loopback/filter](./filter.md) &gt; [isFilter](./filter.isfilter.md)

## isFilter() function

TypeGuard for Filter

**Signature:**

```typescript
export declare function isFilter<MT extends object>(candidate: any): candidate is Filter<MT>;
```

## Parameters

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

Parameter


</th><th>

Type


</th><th>

Description


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

candidate


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

any


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


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

**Returns:**

candidate is [Filter](./filter.filter.md)<!-- -->&lt;MT&gt;