Unable to add property to object using method with this keyword

Question

I'm trying to add a property to an object using a method. Here is the code:

const siddhu = {
    name: 'Siddhu',
    friends: ['Dylan', 'Jordans', 'Aathi'],
    setBestFriend: () => this.bestFriend = this.friends[0],
    setNumOfFriends: () => this.numOfFriends = this.friends.length,
}
siddhu.setBestFriend()
siddhu.setNumOfFriends()

console.log(`${siddhu.name} has ${siddhu.numOfFriends} friends, and his best friend is ${siddhu.bestFriend}`);

For some reason, this doesn't work. I know that changing the this keyword to siddhu fixes the problem, but this isn't ideal, as I want to be able to copy-paste this code multiple times, and I would have to change siddhu every time I did.

Also see [MDN Creating new objects](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Working_with_Objects#creating_new_objects) which shows how to create a custom object which you can reuse multiple times. — Yogi, Oct 01 '22 at 10:42

score 0 · Accepted Answer · answered Oct 01 '22 at 10:43

0

No problem - apparently you can't use this with arrow functions because then this would reference the arrow function. All credit goes to jonrsharpe for telling me!

answered Oct 01 '22 at 10:43

Unable to add property to object using method with this keyword

1 Answers1