Prettying Up Vow.js and Fab.js with Macros

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Up first tonight, I combine my vows.js batches:

var suite = vows.describe('just_playing').
  addBatch({
    'with a query string': {
      // topic + vows
    }
  }).
  addBatch({
    'POSTing data': {
      // topic + vows
    }
  }).export(module);

I had overlooked that batches were only meant for code that needs to run sequentially. My fab.js apps can be accessed at any point, so I might as well consolidate:

var suite = vows.describe('just_playing').
  addBatch({
    'with a query string': {
      // topic + vows
    },
    'POSTing data': {
      // topic + vows
    }
  }).export(module);

Up next, I think I can DRY up my two topics:

var suite = vows.describe('just_playing').
  addBatch({
    'with a query string': {
      topic: function() {
        var topic = this;
        var upstream_listener = player_from_querystring.call(
          function(obj) { topic.callback(null, obj.body); }
        );
        upstream_listener({
          url: { search : "?player=foo&x=1&y=2" },
          headers: { cookie: null }
        });
      },

      // vows
    },
    'POSTing data': {
      topic: function() {
        var topic = this;
        var upstream_listener = player_from_querystring.call(
          function(obj) { topic.callback(null, obj); }
        );
        upstream_listener({body: "foo"});
      },

      // vows
    }
  }).export(module);

The vows.js documentation suggests that GET calls in the topic can be factored out into an api.get call. In my two topics, I am sending data to the upstream via the listener that it returns. I try this:

var api = {
  fab: {
    send_obj: function(obj) {
      return function () {
        var topic = this;
        var upstream_listener = player_from_querystring.call(
          function(obj) { topic.callback(null, obj.body); }
        );
        upstream_listener(obj);
      };
    }
  }
};

With that, I can rewrite my test suite as:

var suite = vows.describe('just_playing').
  addBatch({
    'with a query string': {
      topic: api.fab.send_obj({
        url: { search : "?player=foo&x=1&y=2" },
        headers: { cookie: null }
      }),

      // cows
    },
    'POSTing data': {
      topic: api.fab.send_obj({body: "foo"}),

      // vows
    }
  }).export(module);

Ahhh. That is nice. Unfortunately, when I run the suite, I get:

cstrom@whitefall:~/repos/my_fab_game$ vows --spec

♢ just_playing

/home/cstrom/repos/my_fab_game/test/just_playing.js:14
          function(obj) { topic.callback(null, obj.body); }
                                                  ^
TypeError: Cannot read property 'body' of undefined
    at /home/cstrom/repos/my_fab_game/test/just_playing.js:14:51
    at lib/player_from_querystring.js:25:7
    at Object.<anonymous> (/home/cstrom/repos/my_fab_game/test/just_playing.js:16:9)
    at run (/home/cstrom/.node_libraries/.npm/vows/0.4.5/package/lib/vows/suite.js:125:31)
    at EventEmitter.<anonymous> (/home/cstrom/.node_libraries/.npm/vows/0.4.5/package/lib/vows/suite.js:195:40)
    at EventEmitter.emit (events:42:20)
    at /home/cstrom/.node_libraries/.npm/vows/0.4.5/package/lib/vows/suite.js:147:58
    at EventEmitter._tickCallback (node.js:48:25)
    at node.js:204:9

Aw nuts. Thankfully, that is easily fixed. When I send in non-querystrings, I expect an undefined response. If the response is undefined, then there certainly will not be a body attribute associated with the response, so I rewrite my macro as:

var api = {
  fab: {
    send_obj: function(obj) {
      return function () {
        var topic = this;
        var upstream_listener = player_from_querystring.call(
          function(obj) { topic.callback(null, obj && obj.body); }
        );
        upstream_listener(obj);
      };
    }
  }
};

With that, my suite passes in addition to being nicely compact:

cstrom@whitefall:~/repos/my_fab_game$ vows --spec

♢ just_playing

  with a query string
    ✓ is player
    ✓ has unique ID
    ✓ has X coordinate
    ✓ has Y coordinate
  POSTing data                     
    ✓ is null response

✓ OK » 5 honored (0.090s)

I think that is as good as I can get it. Unless I can come up with further improvements, I will move onto plying my hard-earned vows.js know-how on binary (fab) apps tomorrow.


Day #155