How Value To __proto__ Is Assigned In Javascript?

Recently I have been playing with javaScript prototype object and came across below example. function Foo(){ } Foo.prototype=null; var fooObj=new Foo(); When I look at the foo

Solution 1:

Full details in the specification*, but when you use a constructor function with null for its prototype property, new assigns Object.prototype (well, the default prototype for the realm; Object.prototype for our purposes) as the prototype of the new object.

I believe the only way to create an object with no prototype is Object.create(null).

You can set the prototype to null after creating the object via Object.setPrototypeOf, but in general it's best to avoid changing an object's prototype after you've created it.

---

* Specifically, it's tucked away in GetPrototypeFromConstructor, which says if the type of the constructor's prototype property isn't Object (for this purpose, null is of type Null, not type Object), use the default prototype for the realm.