---
url: /api/core/types/utils/type-deep-merge-reducer-cb.md
description: api documentation of DeepMergeReducerCB from @tsed/core
---

## Usage

```typescript
import { DeepMergeReducerCB } from "@tsed/core/src/utils/deepMerge";
```

> See [/packages/core/src/utils/deepMerge.ts](https://github.com/tsedio/tsed/blob/v8.37.1/packages/core/src/utils/deepMerge.ts#L0-L0).

## Overview

```ts
type DeepMergeReducerCB = (collection: any[], value: any, options?: DeepMergeOptions) => any;
```

## Description

Callback type for custom array merge reducers.