Is an array of ints actually implemented as an array of ints in JavaScript / V8?

There is claim in this article that an array of ints in JavaScript is implemented by a C++ array of ints.

However; According to MDN unless you specifically use BigInts, in JavaScript all numbers are repressed as doubles.

If I do:

cont arr = [0, 1, 2, 3];

What is the actual representation in the V8 engine?

The code for V8 is here on github, but I don’t know where to look: