Why `[1, 2, 3]` is not showing as an `Array(3)` in Console?

Question

When I inspect an instance of an array (like const arr = [1, 2, 3];), the prototype chain for that array will point to Array.prototype.

However, I am not able to understand why Array.prototype is displayed as an empty array (Array(0)) in Chrome console.log()?

I have gone through post1 and post2 but still not able to understand this basic concept.

Why [1, 2, 3] in the console in not showing as an Array(3)?

Answer 1

Array(0) here refers to the [[Prototype]] value, i.e. to Array.prototype.

For instance if you log

const obj = {
  arr: [1, 2, 3]
}

You can see that the actual Array in the arr property is logged as Array(3), but that the [[Prototype]] of this Array is marked as an empty Array.

That's because, like I pointed to you in your now deleted question, Array.prototype is actually an Array itself. See this Q/A for more details.

So if you do something like

Array.prototype[2] = "bar";
const arr = [1, 2, 3];

The Array's Prototype will now say Array(3).