Issue with "Inheritance and the prototype chain": "delete Operator with Object.create and new operator" is mixing up prototypal inheritance and direct assignment

[shuhei]

MDN URL: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Inheritance_and_the_prototype_chain

What information was incorrect, unhelpful, or incomplete?

The section "delete Operator with Object.create and new operator" shows different behaviors of delete with Object.create() and new. However, the difference is coming from the fact that the new example is directly setting a property (this.vertices = [4, 4];) in the constructor instead of using prototypal inheritance. It can give an impression that prototypal inheritance behaves differently depending on how to set it up (Object.create() vs new).

Specific section or headline?

"delete Operator with Object.create and new operator"

What did you expect to see?

It would be great to add an example of prototypal inheritance with new and show that its behavior with delete is the same as Object.create().

Did you test this? If so, how?

function Graph() {
  this.vertices = [4,4];
}
Graph.prototype.a = 123;

var g = new Graph();
console.log(g.a); // print 123
g.a = 234;
console.log(g.a); // print 234
delete g.a;
console.log(g.a); // print 123

MDN Content page report details

• Folder: en-us/web/javascript/inheritance_and_the_prototype_chain
• MDN URL: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Inheritance_and_the_prototype_chain
• GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/javascript/inheritance_and_the_prototype_chain/index.html
• Last commit: 3b80812
• Document last modified: 2021-02-19T19:57:02.000Z

[shuhei]

This was fixed by #3261.