For the last time, ES5 DOESN'T support optional function parameters. gulp --production fails when running on testing when you do that.
*fixes gulp tasks to do gulp --production by default*
Next day : hey, why does gulp keep failing.

IT IS BECAUSE YOU DIDN'T LISTEN TO ME THE LAST 100 TIMES WHEN I SAID OPTIONAL PARAMETERS DOESN'T WORK WHEN MINIFYING

Let's see how you do it now.