Prototype make parameter to False, js

JavaScript
1

Tell us what’s happening:

why in prototype(numLegs) isn’t in beagle? (console.log(beagle))

hasOwnProperty found only first object ? parameter numLegs=False, why?

Your code so far


function Dog(name) {
this.name = name;
}

Dog.prototype.numLegs = 4;

let beagle = new Dog("Snoopy");

let ownProps = [];
let prototypeProps = [];

// Only change code below this line

for( let property in beagle){
if(beagle.hasOwnProperty(property)){
  ownProps.push(property);}
  else {
    prototypeProps.push(property);
  }
}



console.log(ownProps);
console.log(prototypeProps);

console.log(beagle);  //<---

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36 Edg/87.0.664.66.

Challenge: Iterate Over All Properties

Link to the challenge:

2

I’m no expert, but …

Because this is the constructor:

function Dog(name) {
  this.name = name;
}

That constructor is what is being called in this:

let beagle = new Dog("Snoopy");

This …

Dog.prototype.numLegs = 4;

… is changing the prototype but has not changed the constructor. If you check:

console.log(Dog.prototype);
// {numLegs: 4, constructor: ƒ}

Notice that it is a sibling of the constructor, it didn’t change the constructor. If you want it to affect the instances, you’d have to change the constructor.

3

The hasOwnProperty() method returns a boolean indicating whether the object has the specified property as its own property (as opposed to inheriting it or having it delegated from prototype).

1 Like
4

so. it isnt’ added to function.
maybe other function check all(function and prototyp) and will return true

5

Thank You for answer.

6

Thank you for answer.

7

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