server.emit is not a function

test-hapi.js

async function main() {
	const Hapi = require('./lib');
	const server = Hapi.server({ port: 80 });

	server.event('test');
	server.events.once('test', (update) => console.log(update));
	await server.emit('test', 'hello');
	await server.emit('test', 'hello');       // Ignored
}

main()

/* getting the following error
(node:41485) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2): TypeError: server.emit is not a function
(node:41485) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
*/

node --version
v8.8.0