The JavaScript IntelliSense is not working on Visual Studio 2017 RTM editor. I can’t even format the code, nothing is working.
UPDATE: Looks like latest update of VS 2017 (15.3) solve the issue.
This is because of the new javascript language service http://aka.ms/JavaScriptExperimental
To disable and bring back JS, go to: Tools - Options - text editor - Javascript/Typescript - Language service - General and disable the very first option.