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

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[Home](./index.md) &gt; [@loopback/core](./core.md) &gt; [LifeCycleObserverRegistry](./core.lifecycleobserverregistry.md) &gt; [notifyGroups](./core.lifecycleobserverregistry.notifygroups.md)

## LifeCycleObserverRegistry.notifyGroups() method

Emit events to the observer groups

**Signature:**

```typescript
protected notifyGroups(events: (keyof LifeCycleObserver)[], groups: LifeCycleObserverGroup[], reverse?: boolean): Promise<void>;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  events | (keyof [LifeCycleObserver](./core.lifecycleobserver.md)<!-- -->)\[\] | Event names |
|  groups | [LifeCycleObserverGroup](./core.lifecycleobservergroup.md)<!-- -->\[\] | Observer groups |
|  reverse | boolean | _(Optional)_ |

**Returns:**

Promise&lt;void&gt;