method EventEmitter.prototype.onceimport { EventEmitter } from "https://deno.land/std@0.102.0/node/events.ts"; once(eventName: string | symbol, listener: GenericFunction): thisAdds a one-time listener function for the event named eventName. The next time eventName is triggered, this listener is removed and then invoked. Adds a one-time listener function for the event named eventName. The next time eventName is triggered, this listener is removed and then invoked. ParameterseventName: string | symbollistener: GenericFunctionReturnsthis