What is the best way to handle multiple key events in Javascript?

Question

Pressing space bar in game will make a character shoot, pressing space bar when a confirmation box is shown will make this box disappear and pressing space bar in a highscore fo

Answer 1

Functions are first-class objects in javascript, which makes them really powerful. Because of this, your problem can be solved very elegantly.

// the whole thing can be encapsulated 
// into an object actually

function spaceBarHandler() {
  var state = spaceBarHandler.state;
  var actions = spaceBarHandler.actions;

    // execute function if exists
    if (actions[state]) {
      actions[state]();
    }
}

// spaceBar actions
spaceBarHandler.actions = {
  shoot: function() {
    // bang bang
  },
  removeBox: function() {
    // do it...
  }
};

// change current state from outside
// we are in the game
spaceBarHandler.state = "shoot";

// change current state from outside
// confirmation box is shown 
spaceBarHandler.state = "removeBox";

All these cases will be handled by one function. If you want to extend with another case, you just add another function to the actions object. Notice how the whole thing is encapsulated into one object.