Usually, you would have this :
var myApp ={};
(function() {
console.log("Hello");
var var1 = "mark";
myApp.sayGoodbye = function() {
console.log("Goodbye");
};
})();
The main difference is that var1
doesn't clutter the global namespace. After this call, var1
is still the same than before (generally undefined).
As var1
can only be accessed from the function defineds in the closure, it is said "private".
Apart avoiding possible causes of conflicts, it's just cleaner not to keep global variables when useless.
Here, you don't have a local variable but a global one defined as this.var1
. It's probably a bug, or the reason would be found elsewhere in the code.