---
title: "listenerCount | JavaScript maps SDK"
description: "Documentation for MapTiler SDK"
---

> For AI agents: a documentation index is available at [/llms.txt](https://docs.maptiler.com/llms.txt). Markdown versions of all pages are available by appending .md to any URL.

# Function listenerCount

-   listenerCount(emitter: [EventEmitter](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.EventEmitter/), eventName: string | symbol): number[](#listenercount)
    
    A class method that returns the number of listeners for the given `eventName` registered on the given `emitter`.
    
    ```typescript
    import { EventEmitter, listenerCount } from 'node:events';
    
    const myEmitter = new EventEmitter();
    myEmitter.on('event', () => {});
    myEmitter.on('event', () => {});
    console.log(listenerCount(myEmitter, 'event'));
    // Prints: 2
    ```
    
    #### Parameters
    
    -   emitter: [EventEmitter](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.EventEmitter/)
        
        The emitter to query
        
    -   eventName: string | symbol
        
        The event name
        
    
    #### Returns number
    
    #### Since[](#since)
    
    v0.9.12
    
    #### Deprecated[](#deprecated)
    
    Use `emitter.listenerCount()` instead.