Generate number on server and send all clients

[juvahubeku]

Hello. I am developing a multiplayer game. I have a problem. I want the server to create a random number from 1 to 2. And send this number to all customers. But if clients play once, the server must regenerate the number
I wrote such a function. She chooses a number from 1 to 2. And then always returns this number. If you restart the server, it will return a different number.
project - https://fishscape.herokuapp.com/

var map_positions = [
  { map: 1},
  { map: 2},
];
var vibrana_map = { map: 0};
function locateFood(data) {
  var roomId = data;
  var tmpName = room + roomId;
  if (vibrana_map.map == 0) {
    var map_num = Math.floor(Math.random() * 2);
    vibrana_map = map_positions[map_num];
    io.in(tmpName).emit("foodPosition", vibrana_map);
  }
  else {
    io.in(tmpName).emit("foodPosition", vibrana_map);
  }
}