A universal definition pattern for JavaScript libraries. Supports require(), AMD, and browser.

universal-definition-pattern.js

;(function() {
  function myModule() {
  }
  
  if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') {
    module.exports = myModule;
  }
  else {
    if (typeof define === 'function' && define.amd) {
      define([], function() {
        return myModule;
      });
    }
    else {
      window.myModule = myModule;
    }
  }
})();

Let's say assume AMD is dead. Can I do this?

var myModule;
(function () {

    myModule = { foo: 'bar' };

    if ("undefined" !== typeof module && module.exports) {
        module.exports = myModule;
    }
}());

Or do I have to do this?

;(function () {

    var myModule = { foo: 'bar' };

    if ("undefined" !== typeof module && module.exports) {
        module.exports = myModule;
    } else {
        window.myModule = myModule;
    }
}());

1. I definitely think it's safe to drop AMD.
2. What's the point of declaring the var in the global scope?

What's the point of declaring the var in the global scope?

So that it won't interfere with module bundlers that do weird things with window.