generators as object iterator

1.js

// ugly way

var obj = {
  a: 1,
  b: 2,
  c: 3,
  [Symbol.iterator]() {
    var keys = Object.keys(this);
    var idx = 0;
    return {
      next: () => {
        if (idx < keys.length) return { value: this[keys[idx++]], done: false };
        return { value: undefined, done: true };
      }
    };
  }
};
  
for (let v of obj) {
  console.log( v );
}
// 1 2 3

2.js

// better way, generators ftw!

var obj = {
  a: 1,
  b: 2,
  c: 3,
  *[Symbol.iterator]() {
    for (let k of Object.keys(this)) {
      yield this[k];
    }
  }
};
  
for (let v of obj) {
  console.log( v );
}
// 1 2 3