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JavaScript Object-Oriented JavaScript Working with Classes in JavaScript Adding Methods To Our Class

How the method of the class beings passed aound?

Hi, The method within the class not in the constructor, So how it is passed around?

Thanks!

2 Answers

Steven Parker
Steven Parker
216,863 Points

Methods are peers of the constructor, they don't go inside it. But they are still part of the class, so they will exist in any instance of that class.

if i'm going to put properties outside of the constructors they also would be exist in any instance?

Steven Parker
Steven Parker
216,863 Points

Both methods and properties are defined inside the class, but outside of the constructor. Think of the constructor as just another method (but one with a special purpose).

With respect to previous commenters, I think it's important to understand (as Ms. Boucher says) that class is just syntactic sugar for prototypes.

Any object can access a property/method on one of its prototypes. Consider the following:

const greeting = "Hello";
greeting.toLowerCase(); // "hello"

It looks like the method toLowerCase is being accessed on greeting itself, but greeting is just a string... In fact, it is a method of the prototype of the global String object (hence MDN's docs reference to 'String.prototype.toLowerCase'), but greeting can access it because a string automatically shares the same prototype as the String object.

This is all that class does in JS: when you 'instantiate' a class, you create an object and tell it to share the same prototype as the 'class' object, which contains the methods. Therefore you can call them on the 'instantiations' through prototypical inheritance. It is not 'passed around', it is 'borrowed' or 'accessed' from a prototype.

I hope this helps!