I'm trying to call a method in another .js file that looks like this:

if (typeof Shared === "undefined" || !Shared) {
    var Shared = {};
}

Shared.HelperClass = (function ()
{
    // ... private stuff here

    return {
        Init: function()
        {

        },

        TestMethod: function(name)
        {
            return name;
        }
    };

})();

Naturally to call init in Javascript, i'd call:

Shared.HelperClass.Init();

Now I have a TypeScript file i'd like to call this in, but it throws a compiler error because it doesn't know what it is.

How do I tell TypeScript about these methods such that I can call this code from my .ts file?