puppeteer/website/versioned_docs/version-21.9.0/api/puppeteer.eventemitter.once.md

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EventEmitter.once

EventEmitter.once() method

Like on but the listener will only be fired once and then it will be removed.

Signature:

class EventEmitter {
  once<Key extends keyof EventsWithWildcard<Events>>(
    type: Key,
    handler: Handler<EventsWithWildcard<Events>[Key]>
  ): this;
}

Parameters

Parameter	Type	Description
type	Key	the event you'd like to listen to
handler	Handler<EventsWithWildcard<Events>[Key]>	the handler function to run when the event occurs

Returns:

this

this to enable you to chain method calls.