Code snippet 15 - For multiplayer space invaders article

server.js

function subscribeToPlayerInput(channelInstance, playerId) {
  channelInstance.subscribe("pos", (msg) => {
    if (msg.data.keyPressed == "left") {
      if (players[playerId].x - 20 < 20) {
        players[playerId].x = 20;
      } else {
        players[playerId].x -= 20;
      }
    } else if (msg.data.keyPressed == "right") {
      if (players[playerId].x + 20 > 1380) {
        players[playerId].x = 1380;
      } else {
        players[playerId].x += 20;
      }
    }
  });
}