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

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[Home](./index.md) &gt; [@loopback/context](./context.md) &gt; [ContextSubscriptionManager](./context.contextsubscriptionmanager.md)

## ContextSubscriptionManager class

Manager for context observer subscriptions

**Signature:**

```typescript
export declare class ContextSubscriptionManager extends EventEmitter 
```
**Extends:** EventEmitter

## Constructors

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

Constructor


</th><th>

Modifiers


</th><th>

Description


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

[(constructor)(context)](./context.contextsubscriptionmanager._constructor_.md)


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


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

Constructs a new instance of the `ContextSubscriptionManager` class


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

## Properties

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

Property


</th><th>

Modifiers


</th><th>

Type


</th><th>

Description


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<tbody><tr><td markdown="1">

[\_observers](./context.contextsubscriptionmanager._observers.md)


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

`protected`


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

Set&lt;[ContextEventObserver](./context.contexteventobserver.md)<!-- -->&gt; \| undefined


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

A list of registered context observers. The Set will be created when the first observer is added.


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

[\_parentContextEventListener?](./context.contextsubscriptionmanager._parentcontexteventlistener.md)


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

`protected`


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

[ContextEventListener](./context.contexteventlistener.md)


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

_(Optional)_ A listener to watch parent context events


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

[context](./context.contextsubscriptionmanager.context.md)


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`protected`

`readonly`


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[Context](./context.context.md)


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


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

## Methods

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

Method


</th><th>

Modifiers


</th><th>

Description


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

[close()](./context.contextsubscriptionmanager.close.md)


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


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

Close the context: clear observers, stop notifications, and remove event listeners from its parent context.


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

[isSubscribed(observer)](./context.contextsubscriptionmanager.issubscribed.md)


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


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

Check if an observer is subscribed to this context


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<tr><td markdown="1">

[notifyObservers(event, observers)](./context.contextsubscriptionmanager.notifyobservers.md)


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

`protected`


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

Publish an event to the registered observers. Please note the notification is queued and performed asynchronously so that we allow fluent APIs such as `ctx.bind('key').to(...).tag(...);` and give observers the fully populated binding.


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

[subscribe(observer)](./context.contextsubscriptionmanager.subscribe.md)


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


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

Add a context event observer to the context


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

[unsubscribe(observer)](./context.contextsubscriptionmanager.unsubscribe.md)


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


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

Remove the context event observer from the context


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<tr><td markdown="1">

[waitUntilPendingNotificationsDone(timeout)](./context.contextsubscriptionmanager.waituntilpendingnotificationsdone.md)


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


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

Wait until observers are notified for all of currently pending notification events.

This method is for test only to perform assertions after observers are notified for relevant events.


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