method Page.prototype.onceimport { Page } from "https://dotland.deno.dev/x/fresh@1.5.2/tests/deps.ts"; once<K extends keyof PageEventObject>(eventName: K, handler: (event: PageEventObject[K]) => void): EventEmitterType ParametersK extends keyof PageEventObjectParameterseventName: Khandler: (event: PageEventObject[K]) => voidReturnsEventEmitter