Array.prototype.fill() with object passes reference and not new instance

Question

I was toying a bit and was trying to instantiate a new array of length x, where all elements of that array were initialized to a value y:

Answer 1

Ilias Karim's answer is most excellent. I just did the following:

a = Array.from({length:l}, () => new Array(c).fill(prefix));

to create a pre-filled 2D array of the specified size, l by c, filled with prefix. Now my code can fill in the slots in the 2D matrix that need non-prefix values.