Test coverage is not the best. I've just added some demo test to showcase how the codebase can be tested.
There is no anti-cheat in place, one user could easly send numbers that are out of what's allowed. The code trusts the users.

Both players use the same codebase. There are functions to manage the matchmaking and understand if the current process is player 1 or 2.

Install dependencies (node v12.16.2)

npm i

To start the game, run the app twice in two different terminals with

npm start

To start one of the player in interactive mode, run

npm start -- -i