commonjs-exports-fallback.js

// As per http://wiki.commonjs.org/wiki/Modules/1.1
// 1. In a module, there is a free variable "require", that is a Function.
// 2. In a module, there is a free variable called "exports", that is an object.
// 3. In a module, there must be a free variable "module", that is an Object.
//x3.1 The "module" object must have a read-only, don't delete "id" property.
// No check for 3.1 since nodejs's module.id is both writable and deletable.
//x2.1 modules must use the "exports" object as the only means of exporting.
// Export through "module.exports" is much simpler though.

myModule = {}
myModule.a = 123


;(function (_exports, _name) {
  let isCommonJs = (() => {
    if ((typeof require !== 'function') || (require === this.require)) return false
    if ((typeof exports !== 'object') || (exports === this.exports)) return false
    if ((typeof module !== 'object') || (module === this.module)) return false
    return true
  })()
  if (isCommonJs) { module.exports = _exports }
  else { this[_name] = _exports }
})(myModule, 'myModule')