gistfile1.js

MYAPP.namespace("MYAPP.utils.set");
MYAPP.utils.set = (function() {
    // dependencies
    var someDep = OTHERLIB.util.collections,

    // private properties
    privateVar = "private",

    // methods
    privateMethod = function() {
        ...
    },

    union = function() { ... },
    intersection = function() { ... },
    difference = function() { ... }; 

    // end var

    // one-time init procedures

    // public API
    return {
        union: union,
        intersection: intersection,
        difference: difference
    };
})();