Declaring methods in different way

Asked Jan 13 '21 at 07:20

Active Jan 13 '21 at 07:31

Viewed 36 times

I have a question about declaring methods for a function in JavaScript. Suppose that I declare a function Monster in these two following ways: First way:

function Monster() {
  this.growl = () => {
    console.log('grrr!');
  }
}

Second Way:

function Monster() {
}
Monster.prototype.growl = () => {
  console.log('grrr!');
}

The question is: when I instantiate n monster I do create n methods for both way of declaration or I create only one method for all the monsters I instantiated?

edited Jan 13 '21 at 07:31

asked Jan 13 '21 at 07:20

Giovanni

4

n methods in the first case, only one in the second case. – VLAZ Jan 13 '21 at 07:21
4

Both `this.growl() = ...` and `Monster.prototype.growl() = ...` are syntax errors – Hao Wu Jan 13 '21 at 07:22
@HaoWu you're right I corrected it – Giovanni Jan 13 '21 at 07:32
@VLAZ can you kindly explain me why? – Giovanni Jan 13 '21 at 07:37
First case it's adding a method on each instance. Second case adds one method to the prototype that all instances share. – VLAZ Jan 13 '21 at 07:40
Don't use arrow functions for methods, they cannot access the instance using `this` – Bergi Jan 13 '21 at 07:47

Declaring methods in different way

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