__proto__ VS. prototype in JavaScript

Question

This figure again shows that every object has a prototype. Constructor function Foo also has its own __proto__ which is Function.prototype, a

Answer 1

Explanatory example:

function Dog(){}
Dog.prototype.bark = "woof"

let myPuppie = new Dog()

now, myPupppie has __proto__ property which points to Dog.prototype.

> myPuppie.__proto__
>> {bark: "woof", constructor: ƒ}

but myPuppie does NOT have a prototype property.

> myPuppie.prototype
>> undefined

So, __proto__ of mypuppie is the reference to the .prototype property of constructor function that was used to instantiate this object (and the current myPuppie object has "delegates to" relationship to this __proto__ object), while .prototype property of myPuppie is simply absent (since we did not set it).

Good explanation by MPJ here: proto vs prototype - Object Creation in JavaScript