CODEWITHSUNDEEP
javascript
John
John

Reputation: 381

How to use Object.defineProperties()?

Below I am trying to define properties of an object using defineProperties function, but I am getting unexpected outcome when I print last line in this script. I expect 2005 to be logged at console, but I keep getting 2004. Same applies to other properties, like edition. Am I using this defineProperties function incorrectly?

var book = {};
Object.defineProperties(book, {
  _year: {
    value: 2004
  },
  edition: {
    value: 1
  },
  year: {
    get: function() {
      return this._year;
    },
    set: function(newValue) {
      if (newValue > 2004) {
        this._year = newValue;
        this.edition += newValue - 2004;
      }
    }
  }
});


console.log(book);
console.log(book.year);

book.year = 2005;

console.log(book);
console.log(book.year);

Upvotes: 0

Views: 33

Answers (1)

Quentin
Quentin

Reputation: 944538

You defined _year as read only, so this._year = newValue fails (silently). You need to make it writable.

  _year: {
    value: 2004,
    writable: true
  },

Upvotes: 2

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