Notification Examples is missing function displayNoPermissionError

[bochap]

cc @gauntface

Type of Issue

Is this an issue with the demos, the content or is this a content request?

Demo for Notification Examples throws a javascript exception. Uncaught (in promise) ReferenceError: displayNoPermissionError is not defined at Promise.then (notification-examples.js:630). Looking into https://github.com/gauntface/web-push-book/blob/master/src/demos/notification-examples/notification-examples.js it appears that displayNoPermissionError is not available. This only happens if you reject the permission for Notification API

Details....

If a bug with the demo What was the expected outcome vs actual outcome and what browsers are affect, please include versions.

Page: https://web-push-book.gauntface.com/demos/notification-examples/

It should log to console or show something that displayNoPermissionError does when you reject to the permission to use Notification API. Currently it logs an error in the javascript console.

Test on Browsers: Chrome Version 67.0.3396.99 (Official Build) (64-bit) [Same behavior on Incognito] Firefox Quantum 60.0.1