[SalesForce] Lightning: Are there any global variables to check current user profile or custom permissions

Use custom labels in Lightning components with the $Label global value provider.

Use this syntax to access custom labels in Lightning components:

$Label.c.labelName for the default namespace

$Label.namespace.labelName if your org has a namespace Here are some examples.

Label in a markup expression using the default namespace
{!$Label.c.labelName}

Label in JavaScript code if your org has a namespace

$A.get("$Label.namespace.labelName")

How about using static resources and defining the global variables like below

Approach 1 involves using a static resource file to store all the global values

Here is how a code in your static resource look like

(function(w){
  "use strict"; //Optional because LC on LockerService active runs in strict mode

 var globalConstants = {
    "variable1":"abc",
    "variable2":"zyz"
  };

  w.globalvalues = globalConstants;

})(window);

And then in lightning component you will use like below

 ltng:require scripts="{!$Resource.TestScript}" afterScriptsLoaded="{!c.afterScriptsLoaded}" />

 afterScriptsLoaded : function(cmp){
   globalvalues.variable1; 
   globalvalues.variable2; 
 }

Approach 2: An application event fired on init call and all the components handle it .