@loopback/docs/site/apidocs/context.mergeinterceptors.md

Documentation for LoopBack 4

---
lang: en
title: 'API docs: context.mergeinterceptors'
keywords: LoopBack 4.0, LoopBack 4
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permalink: /doc/en/lb4/apidocs.context.mergeinterceptors.html
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[Home](./index.md) &gt; [@loopback/context](./context.md) &gt; [mergeInterceptors](./context.mergeinterceptors.md)

## mergeInterceptors() function

Adding interceptors from the spec to the front of existing ones. Duplicate entries are eliminated from the spec side.

For example:

- \[log\] + \[cache, log\] =<!-- -->&gt; \[cache, log\] - \[log\] + \[log, cache\] =<!-- -->&gt; \[log, cache\] - \[\] + \[cache, log\] =<!-- -->&gt; \[cache, log\] - \[cache, log\] + \[\] =<!-- -->&gt; \[cache, log\] - \[log\] + \[cache\] =<!-- -->&gt; \[log, cache\]

<b>Signature:</b>

```typescript
export declare function mergeInterceptors(interceptorsFromSpec: InterceptorOrKey[], existingInterceptors: InterceptorOrKey[]): GenericInterceptorOrKey<InvocationContext>[];
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  interceptorsFromSpec | <code>InterceptorOrKey[]</code> | Interceptors from <code>@intercept</code> |
|  existingInterceptors | <code>InterceptorOrKey[]</code> | Interceptors already applied for the method |

<b>Returns:</b>

`GenericInterceptorOrKey<InvocationContext>[]`