Loading a single model with Ember.js

Question

I'm trying to write a pretty simple app: I have some games (say chess, tictactoe... whatever), and there are several boards of each game. I want to show a list of games, and then show a list of boards when you click on a game.

But I'm facing a lot of problems. I'll first describe them, and I'll paste the code after that:

1. The list of games is correctly shown. No problem here.

2. When I click a game, I get this error:

   Uncaught Error: assertion failed: an Ember.CollectionView's content must implement Ember.Array. You passed <(generated game controller):ember237>

   BUT if I press F5 or write the URL manually, everything works fine . And I have no idea why.

   UPDATE : I've seen that if I change the games template, changing the {{#linkTo}} with a hand-written link, everything works OK:

   • This is the non-working linkTo: {{#linkTo 'game' game}}{{game.name}}{{/linkTo}} . It builds the URL correctly, but it fails when I click on it.
   • This is a hand-written <a> tag: <a href="#/games/{{unbound game.id}}">{{game.name}}</a> . It works perfectly.

3. The Url of each board should follow this format:

   /games/1/boards/5

   But when I write the {{#linkTo 'board' board}} what I get is:

   /games/undefined/boards/5

Here is the code (You can see a "working" copy here in JBin . But it's not functional, because it relays on a local REST app):

The Router:

MGames.Router.map(function () {
    this.resource('games', function () {
        this.resource ('game', {path: '/:game_id'}, function () {
            this.resource('board', {path: '/boards/:board_id'});
        });
    });
});

MGames.IndexRoute = Ember.Route.extend({
    redirect: function () {
        this.transitionTo('games');
    }
});

MGames.GamesRoute = Ember.Route.extend ({
    model: function() {
        return MGames.Game.findAll();
    }
});

MGames.GameRoute = Ember.Route.extend ({
    model: function(params) {
        return MGames.Board.findAllByGame(params.game_id);
    }
});

MGames.BoardsRoute = Ember.Route.extend ({
    model: function(params) {
        return this.modelFor('game').then(
            function (game) {
                return MGames.Board.find(game.get('id'), params.board_id);
            }
        );
    }
});

The models:

MGames.Game = Ember.Object.extend({
    id: null,
    name: null,
    icon: null
});

MGames.Game.reopenClass({
    findAll: function() {
        var url = [MGames.GAMES_API_URL];
        url.push ('games');
        url = url.join('/');

        var result = Ember.ArrayProxy.create({ content: [] });

        $.getJSON(url).then (
            function (response) {
                response.forEach(function (child) {
                    result.pushObject (MGames.Game.create(child));
                });
            }
        );

        return result;
    },

    find: function (id) {
        var url = [MGames.GAMES_API_URL];
        url.push ('games');
        url.push (id);
        url = url.join('/');

        var game = MGames.Game.create({ isLoaded: false });

        $.getJSON(url).then (
            function(response) {
                game.setProperties(response);
                game.set('isLoaded', true);
            }
        );

        return game;
    }
});

MGames.Board = Ember.Object.extend({
    id: null,
    name: null,
    owner: null,
    game: null,
    is_public: null,
    created_at: null
});

MGames.Board.reopenClass({
    findAllByGame: function (game) {
        var url = [MGames.GAMES_API_URL];
        url.push ('games');
        url.push (game);
        url.push ('boards');
        url = url.join('/');

        var result = Ember.ArrayProxy.create({ content: [] });

        $.getJSON(url).then (
            function (response) {
                console.log (response);
                response.forEach(function (child) {
                    result.pushObject (MGames.Board.create(child));
                });
            }
        );

        return result;
    },

    find: function (game, board) {
        url = [MGames.GAMES_API_URL];
        url.push ('games');
        url.push (game);
        url.push ('boards');
        url.push (board);
        url = url.join('/');

        var result = MGames.Board.create();

        $.getJSON(url).then (
            function(response) {
                result.setProperties(response);
            }
        );

        return result;
    }
});

And the template:

<!doctype html>
<html>
<head>
  <meta charset="utf-8">
  <title>MGames</title>
  <link rel="stylesheet" href="css/bootstrap.css">
  <link rel="stylesheet" href="css/main.css">
</head>
<body>

  <script type="text/x-handlebars">
    <div class="navbar navbar-fixed-top">
      <div class="navbar-inner">
        <div class="container">
          <div class="nav-collapse collapse">
            <ul class="nav">
              <li class="active">{{#linkTo 'index' class="brand"}}MGames{{/linkTo}}</li>
            </ul>
          </div>
        </div>
      </div>
    </div>

    <div class="container">
      {{outlet}}
    </div>
  </script>

  <script type="text/x-handlebars" id="games">
    <div class="row">
      <header id="header">
        <h1>Games</h1>
      </header>
      <ul>
      {{#each game in controller}}
      <li>
        {{#linkTo 'game' game}}{{game.name}}{{/linkTo}}
      </li>
      {{/each}}
      </ul>

      {{outlet}}
    </div>
  </script>

  <script type="text/x-handlebars" id="game">
    <div class="row">
      <div class="span3" id="boards">
        <header id="header">
          <h1>Boards</h1>
        </header>

        <ul id="board-list">
          {{#each board in controller}}
          <li>
            {{#linkTo 'board' board}}{{board.name}}{{/linkTo}}
          </li>
          {{/each}}
        </ul>
      </div>
      <div class="span9">
        {{outlet}}
      </div>
    </div>
  </script>

  <script type="text/x-handlebars" id="board">
    <header id="header">
      <h1>{{game.name}} - {{name}} <small>{{owner.nickname}}</small></h1>
    </header>
  </script>

  <script src="js/libs/jquery.js"></script>
  <script src="js/libs/bootstrap.js"></script>
  <script src="js/libs/handlebars.js"></script>
  <script src="js/libs/ember.js"></script>

  <script src="js/application.js"></script>
  <script src="js/router.js"></script>
  <script src="js/models/game.js"></script>
  <script src="js/models/user.js"></script>
</body>
</html>

Answer 1

Ok, I finally figured out the problem. In my gameRoute I wrote this:

MGames.GameRoute = Ember.Route.extend ({
    model: function(params) {
        return MGames.Board.findAllByGame(params.game_id);
    }
});

It worked when I write the URL directly in the browser bar, because Ember calls the model function, but when following a {{#linkTo}} the model is the one passed as parameter, so the model function isn't called.

So the working code is this one (a little bit simplified):

MGames.GameRoute = Ember.Route.extend ({
    model: function (params) {
        // This is only called when loading the URL directly,
        // not following a link. We load the game, and in the
        // setupController we'll load the boards.
        return MGames.Game.find(params.game_id);
    },
    setupController: function(controller, game) {
        // This is *always* called, so we load the boards
        model = MGames.Board.findAllByGame(game.id);
        controller.set('model', model);
    }
});

Answer 2

The board route that you are linking to has 2 dynamic segments, but you are providing only one. You need to change to,

{{#linkTo 'board' game board}}The board{{/linkTo}}

The undefined error is probably due to the ArrayController not getting a board as the corresponding game id is being passed as undefined . The above change should fix that too.