Library is not transcompiled?

[LeoSeyers]

Hello,
I'm using Laravel Mix (which is a basic Webpack wrapper) to bundle my assets into a vendors.js file and there are a few "let" left in my file when I hit the production command. I don't care much myself about old users stucked with iOS 9.x but maybe some other people do?

Unexpected use of reserved word 'let' in strict mode

I assume it may be related to other issues :
#12
#9

Have a good day
Leo