Generator에서 for-in 사용시 hasOwnProperty 필요 여부 about functionales HOT 1 CLOSED

function *valuesIter(obj) {
  for (const key in obj) yield obj[key];
}

function each(f, coll) {
  const iter = typeof coll[Symbol.iterator] == 'function' ?
    coll : valuesIter(coll);

  for (const val of iter) f(val);

  return coll;
}

const users = {
  5: { id: 5, name: 'YB' },
  19: { id: 19, name: 'BX' },
  27: { id: 27, name: 'MD' }
};

each(u => console.log(u.name), users);
// YB
// BX
// MD

function CustomObject(object) {
  Object.assign(this, object);
}
CustomObject.prototype.get = function(key) {
  return this[key];
};
CustomObject.prototype.set = function(key, val) {
  this[key] = val;
  return this;
};

const customObject = new CustomObject({
  a: 'A',
  b: 'B'
});

console.log(customObject);
each(a => console.log(a), customObject);
// A
// B
// f (key) {
//     return this[key];
//   }
// f (key, val) {
//     this[key] = val;
//     return this;
//   }

function *valuesIter2(obj) {
  for (const key in obj)
    if (obj.hasOwnProperty(key)) yield obj[key];
}
each(console.log, valuesIter2(customObject));
// A
// B

class CustomObject2 {
  constructor(object) {
    Object.assign(this, object);
  }
  get(key) {
    return this[key];
  }
  set(key, val) {
    this[key] = val;
    return this;
  }
}
each(console.log, new CustomObject2({a:1, b: 2}));
// 1
// 2