PhpStorm “Let definition are not supported by current JavaScript version”

Question

I am trying to be a good little programmer and use the new tools available for coding JavaScript. Therefore I\'m trying to use let instead of var t

Answer 1

Go to

Settings / Languages & Frameworks / JavaScript

(it may be Preferences / Languages & Frameworks / JavaScript on some OSes)

...and set the "JavaScript language version" to "ECMAScript 6" (or, if they've updated to reflect current naming, "ECMAScript 2015" — or "ECMAScript 2016" or later if you're coding to a newer spec):