Hack to test if an Object is "empty"

isObjectEmpty.js

Object.prototype.isEmpty = function () {
  return !Object.keys(this)
    .map(k => this.hasOwnProperty(k), this) // bind the value of `this` for each callback
    .length
}

// Usage: 
// > let obj0 = {}
// > let obj1 = {foo: 1, bar: 2}
// > obj0.isEmpty() // true
// > obj1.isEmpty // false