Create a 2D Array based on seed/key

firstly the language Im writing in is node (javascript) but really Im looking for the computer science behind it, and how to actually do it, not just the code.

Basically what I have is a 2,000 x 2,000 two dimensional array (every entry in the 2,000 entry long array has its own 2,000 entries). Now inside this array i have values 0, 1, 2 3, etc. What I want to do is generate this array based on a key, idc how long, just a reasonable length. I want the same key to generate the same array if its the same key and a different one if its a different key.

I understand that the key will most likely be a decimal of some sort I multiply a bunch of constants by, but tbh thats just my own thinking I really have no Idea where to start. Essentially its like how minecraft takes a seed and turns it into an identical map for the same seed.