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EventEmitter.defaultMaxListeners - node__events.d.ts - Node documentation
property EventEmitter.defaultMaxListeners

Usage in Deno

```typescript import { EventEmitter } from "node:node__events.d.ts"; ```
By default, a maximum of `10` listeners can be registered for any single event. This limit can be changed for individual `EventEmitter` instances using the `emitter.setMaxListeners(n)` method. To change the default for _all_`EventEmitter` instances, the `events.defaultMaxListeners` property can be used. If this value is not a positive number, a `RangeError` is thrown. Take caution when setting the `events.defaultMaxListeners` because the change affects _all_ `EventEmitter` instances, including those created before the change is made. However, calling `emitter.setMaxListeners(n)` still has precedence over `events.defaultMaxListeners`. This is not a hard limit. The `EventEmitter` instance will allow more listeners to be added but will output a trace warning to stderr indicating that a "possible EventEmitter memory leak" has been detected. For any single `EventEmitter`, the `emitter.getMaxListeners()` and `emitter.setMaxListeners()` methods can be used to temporarily avoid this warning: ```js import { EventEmitter } from 'node:events'; const emitter = new EventEmitter(); emitter.setMaxListeners(emitter.getMaxListeners() + 1); emitter.once('event', () => { // do stuff emitter.setMaxListeners(Math.max(emitter.getMaxListeners() - 1, 0)); }); ``` The `--trace-warnings` command-line flag can be used to display the stack trace for such warnings. The emitted warning can be inspected with `process.on('warning')` and will have the additional `emitter`, `type`, and `count` properties, referring to the event emitter instance, the event's name and the number of attached listeners, respectively. Its `name` property is set to `'MaxListenersExceededWarning'`.

Type

number