Mistake on the "Object.prototype.constructor" page

MDN
1

Hello,

On https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/constructor,

Towards the end of the page, there is an example meant to show an error when changing the constructor, starting with “function ParentWithStatic() {}”.

However when I copy it to the console and create an instance, everything works as is, and I encounter no error,

Even though the comment suggests there should be one when calling the method getOffsetByInitialPosition

// error undefined is not a function, since the constructor is Child
2

Hello @Rony_Gozes

could you share the full code you test

and have a nice day :slight_smile:

3

Hey, this is the code that works just fine for me:

function ParentWithStatic() {}

ParentWithStatic.startPosition = { x: 0, y:0 } // Static member property
ParentWithStatic.getStartPosition = function getStartPosition() {
return this.startPosition
}

function Child(x, y) {
this.position = {
x: x,
y: y
}
}

Child = Object.assign(Child, ParentWithStatic) // copies over the static members from ParentWithStatic to Child
Child.prototype = Object.create(ParentWithStatic.prototype)
Child.prototype.constructor = Child

Child.prototype.getOffsetByInitialPosition = function getOffsetByInitialPosition() {
let position = this.position
let startPosition = this.constructor.getStartPosition() // error undefined is not a function, since the constructor is Child

return {
offsetX: startPosition.x - position.x,
offsetY: startPosition.y - position.y
}
};

let child = new Child(1,2)

console.log(child.getOffsetByInitialPosition())

4

i think you are right but let me ask @chrisdavidmills in case i miss something

and have a nice day both of you :slight_smile: