foobar.js

var yadda = (function() {
    var myObject = {};
    var pubVar = 123;
    var privVar = 456;
    var someDefaultOptions = {};
    
    function public1() {
      // ...
        return 'allKindsOfInterestingStuff';
    }
    function public2(x) {
        var y = private1(x);
        y += 'yay';
        return y;
    }
    
    // not for public use
    function private1(inpupt) {
        var output = mangle(input);
        return output;
    }
    
    myObject.public1 = public1;
    myObject.public2 = public2;
    myObject.pubVar = pubVar;
    
    return myObject;
    
})();

foo = yadda.public1();