CODEWITHSUNDEEP
javascriptjquery
megler
megler

Reputation: 216

Replacing if else if statements with something more efficient

I'm trying to learn coding by building a simple text game. The end game is going to have 4 rooms. You'll start in room 1, exit west to room 2, exit south to room 3, and finally exit east in room 4. (clockwise).

Anyway, my starting code is from a YouTube tutorial I found that consists of all if / else if statements. I already see that's terribly inefficient. My question is how do I improve this code?

I'm guessing I should make each room and it's contents an object (ie. Room 1 has a sword in it, so the object would contain the location of the room and the sword). I'm also guessing if I have a monster in a room, he'd be his own object.

My problem is if the above is correct (object) - I don't understand how to use the object once I create it. ie. if the user types "take sword" how do I call the object to do that?

If I'm on the complete wrong track, please point me back in the right direction.

Here's the current code for the first room:

$("form").submit(function() {
    var input = $("#commandLine").val();

    function check() {
        check = true;
    }

    if (input == "help") {
        $("#messageHelp").clone().insertBefore("#placeholder").fadeIn(1000);
        check();
    }

    if (input == "take sword" && currentRoom == "nCorridor") {
        $("<p>You picked up a sword.</p>").hide().insertBefore("#placeholder").fadeIn(1000);
        check();
    }
    else if (input == "take sword" && currentRoom != "nCorridor") {
        $("<p>The sword is not here.</p>").hide().insertBefore("#placeholder").fadeIn(1000);
        check();
    }
    else if (input != "take sword" && input != "help") {
        $("<p>I don't understand " + input +  ".</p>").hide().insertBefore("#placeholder").fadeIn(1000);
    }

    $("#commandLine").val("");
});

Ideally, I'd like to eliminate or greatly reduce my need to use if and else if statements for something more efficient.

Upvotes: 0

Views: 133

Answers (1)

Guffa
Guffa

Reputation: 700252

First let's improve the logic in the if statements to reduce the duplicate conditions, to see how far that gets you:

if (input == "help") {

  $("#messageHelp").clone().insertBefore("#placeholder").fadeIn(1000);
  check();

} else if (input == "take sword") {

  if (currentRoom == "nCorridor") {
    $("<p>You picked up a sword.</p>").hide().insertBefore("#placeholder").fadeIn(1000);
    check();
  } else {
    $("<p>The sword is not here.</p>").hide().insertBefore("#placeholder").fadeIn(1000);
    check();
  }

} else {

  $("<p>I don't understand " + input +  ".</p>").hide().insertBefore("#placeholder").fadeIn(1000);

}

Another way to determine the action depending on input is using a switch, which may be more useful when you get more options:

switch (input) {

  case "help":
    $("#messageHelp").clone().insertBefore("#placeholder").fadeIn(1000);
    check();
    break;

  case "take sword":
    if (currentRoom == "nCorridor") {
      $("<p>You picked up a sword.</p>").hide().insertBefore("#placeholder").fadeIn(1000);
      check();
    } else {
      $("<p>The sword is not here.</p>").hide().insertBefore("#placeholder").fadeIn(1000);
      check();
    }
    break;

  default:
    $("<p>I don't understand " + input +  ".</p>").hide().insertBefore("#placeholder").fadeIn(1000);

}

To go on and using objects for keeping track of items, you could create an object for the sword (with just the location for now):

var sword = {
  room: "nCorridor"
};

In the code you could use the object like this:

  if (currentRoom == sword.room) {
    $("<p>You picked up a sword.</p>").hide().insertBefore("#placeholder").fadeIn(1000);
    check();
  } else {
    $("<p>The sword is not here.</p>").hide().insertBefore("#placeholder").fadeIn(1000);
    check();
  }

From there you can add more properties and methods to items. The objects might for example have methods that you can use to determine what you can do with them, like that the item apple can be eaten, but the item sword can not.

Upvotes: 1

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