Service Worker line error in Dreamweaver

[#1]

Hello everybody. Working over Dreamweaver cs6, over javascript code for service worker, shows an error over this line: 

let deferredPrompt = null;

but code not the issue.

[#2]

Hello everybody. Working over Dreamweaver cs6, over javascript code for service worker, shows an error over this line: 

let deferredPrompt = null;

but code not the issue.

[#3 · Accepted solution]

Dreamweaver CS6 was written about 8 years ago, way before ECMAScript 6. It is therefore best to ignore the message.

[#4]

Legacy CS6 is beyond support and no longer updated.   Switch to a modern code editor (Brackets, Sublime, VS Code, DW CC 2020, etc...). 

[#5]

Excellent Nancy, Ben. I would update my coding framework.