define a module which can use in Node, AMD, CMD and Browser by warp the code in a closure.

hello.js

;(function (name, definition) {
  // test if the context is AMD or CMD
  var hasDefine = typeof define === 'function',
    // test if the context is Node
    hasExports = typeof module !== 'undefined' && module.exports;
    
  if (hasDefine) {
    // AMD or CMD
    define(definiton);
  } else if (hasExports) {
    // Node
    module.exports = definiton();
  } else {
    // in browser, this point to object `window`
    this[name] = definition();
  }
})('hello', function() {
  var hello = function() {};
  return hello;
});