What is the difference between the two versions of functions

Question

Can some one explain what is the difference between these two code blocks? Why would we ever need the first type when second one is more concise.

First

var Utility;
(function (Utility) {
    var Func = (function () {
        function Func(param1, param2) {
            var self = this;
            this.Owner = param2;
        }
        return Func;
    })();
    Utility.Func = Func;
})(Utility || (Utility = {}));

Second:

var Utility;
(function (Utility) {
    Utility.Func = function (param1, param2) {
            var self = this;
            this.Owner = param2;
        }
})(Utility || (Utility = {}));

context: First version was code generated by typescript compiler and I am trying to understand why did it generate the first instead of a simpler second.

Answer 1

The only difference between the code blocks is that the first has a function scope around the code that creates the Func function. The only reason to do that would be to create a scope where you can declare variables that would not be available in the outer scope:

var Utility;
(function (Utility) {
    var Func = (function () {

        var x; // a variable in the inner scope

        function Func(param1, param2) {
            var self = this;
            this.Owner = param2;
        }
        return Func;
    })();

    // the variable x is not reachable from code here

    Utility.Func = Func;
})(Utility || (Utility = {}));