Syntaxerror: Let Is A Reserved Identifier On Firefox

I am using those code below 'use strict'; jQuery(document).ready(function($) { function CMB2ConditionalsInit(context) { if(typeof context === 'undefined') {

Solution 1:

As you can see the let keyword isn't supported on FF yet: https://kangax.github.io/compat-table/es6/

You will need to change it to var, or transpile your code with babel