tictactinytoe

2 player tictactoe-hosting TCP server in 640 bytes:

F=_=>{x=o=z=0;t=1};F();require("net").createServer(c=>{h="\n";w=s=>c.write(s+h);if(o)return w("Game in progress");c.m={};c.w=w;z++?(o=c,o.W=x.w,x.W=w):x=c;G=e=>{for(l="",i=1;i<=9;i++)l+=i in x.m?"X":o&&i in o.m?"O":i,l+=i%3?"|":h;e.w(l)};G(c);c.on("end",_=>c.W("Player left")).on("data",d=>{if(t^c==x)return;v=parseInt(d);if(isNaN(v)||v<1||v>9||v in{...x.m,...o.m})return c.w("Invalid move");t=c.m[v]=1-t;G(x);o&&G(o);f=i=>i<24?"123147159369789753258456".slice(i,i+3).split("").every(j=>j in c.m)||f(i+3):0;if(f(0))throw c.w("You won"),c.W("You lost");if(z++>9)throw r="Draw",c.w(r),c.W(r)})}).listen(9191);process.on("uncaughtException",F)

Tested with node v14.16.1

node -e 'F=_=>{x=o=z=0;t=1};F();require("net").createServer(c=>{h="\n";w=s=>c.write(s+h);if(o)return w("Game in progress");c.m={};c.w=w;z++?(o=c,o.W=x.w,x.W=w):x=c;G=e=>{for(l="",i=1;i<=9;i++)l+=i in x.m?"X":o&&i in o.m?"O":i,l+=i%3?"|":h;e.w(l)};G(c);c.on("end",_=>c.W("Player left")).on("data",d=>{if(t^c==x)return;v=parseInt(d);if(isNaN(v)||v<1||v>9||v in{...x.m,...o.m})return c.w("Invalid move");t=c.m[v]=1-t;G(x);o&&G(o);f=i=>i<24?"123147159369789753258456".slice(i,i+3).split("").every(j=>j in c.m)||f(i+3):0;if(f(0))throw c.w("You won"),c.W("You lost");if(z++>9)throw r="Draw",c.w(r),c.W(r)})}).listen(9191);process.on("uncaughtException",F)'

• Non-minified code is in tictactinytoe.js
• Use netcat to connect to the server and play
• Both players must Ctrl-C and reconnect for a new game

netcat localhost 9191  # first player: X
netcat localhost 9191  # second player: O

Docker

docker run --rm -it node:14-alpine node -e 'F=_=>{x=o=z=0;t=1};F();require("net").createServer(c=>{h="\n";w=s=>c.write(s+h);if(o)return w("Game in progress");c.m={};c.w=w;z++?(o=c,o.W=x.w,x.W=w):x=c;G=e=>{for(l="",i=1;i<=9;i++)l+=i in x.m?"X":o&&i in o.m?"O":i,l+=i%3?"|":h;e.w(l)};G(c);c.on("end",_=>c.W("Player left")).on("data",d=>{if(t^c==x)return;v=parseInt(d);if(isNaN(v)||v<1||v>9||v in{...x.m,...o.m})return c.w("Invalid move");t=c.m[v]=1-t;G(x);o&&G(o);f=i=>i<24?"123147159369789753258456".slice(i,i+3).split("").every(j=>j in c.m)||f(i+3):0;if(f(0))throw c.w("You won"),c.W("You lost");if(z++>9)throw r="Draw",c.w(r),c.W(r)})}).listen(9191);process.on("uncaughtException",F)'

• Use docker inspect <container> | grep -m 1 '"IPAddress":' to find IP for netcat
• To exit the server use docker stop <container>