Publish/Subscribe Pattern & Vanilla JavaScript
https://en.wikipedia.org/wiki/Publish–subscribe_pattern
MDN
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/get
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/set
https://developer.mozilla.org/en-US/docs/Learn/HTML/Introduction_to_HTML/Marking_up_a_letter
blogs
http://bdadam.com/blog/a-simple-pubsub-module-in-javascript.html
https://stackoverflow.com/questions/13512949/why-would-one-use-the-publish-subscribe-pattern-in-js-jquery
https://hackernoon.com/observer-vs-pub-sub-pattern-50d3b27f838c
https://www.rabbitmq.com/tutorials/tutorial-three-javascript.html
https://docs.microsoft.com/en-us/sharepoint/dev/sp-add-ins/complete-basic-operations-using-javascript-library-code-in-sharepoint
PubSub
publish/subscribe (PubSub) pattern
http://bdadam.com/blog/a-simple-pubsub-module-in-javascript.html
Pub/Sub JavaScript
delete ???
https://davidwalsh.name/pubsub-javascript