How to get document _id from Meteor cursor? - meteor

Question

I have rewritten this question as i now understand my problem a bit more. The answers below remain relevant.
I have the following query which returns a record.
Template.game.helpers({
Game: function () {
var myGame = Games.findOne(
{
game_minutes: {$gt: MinutesSinceMidnightNow},
court_id: court,
game_date: {$gt: lastMidnight}
},
{
sort: {game_minutes: 1}
}
); // find
console.log(myGame);
console.log(myGame._id);
return myGame;
} // game function
}); //template scoreboard.helpers
Meteor.startup(function () {
Meteor.call('removeGames', court, MinutesSinceMidnightNow);
for(var i=0;i<incomingGames.length;i++){
var game = incomingGames[i];
var gameTime = game.game_time;
if ( MinutesSinceMidnightGameTime(gameTime) > MinutesSinceMidnightNow ) {
console.log("game # " + i + ' game time ' + MinutesSinceMidnightGameTime(gameTime) + ' now' + ' ' + MinutesSinceMidnightNow);
Meteor.call('insertGame', game);
} // if
} // for
// game = Meteor.call("nextGame", MinutesSinceMidnightNow, court, lastMidnight);
console.log(MinutesSinceMidnightNow + ', ' + court + ', ' + lastMidnight);
}); // startup
The first console.log shows a game object which includes the _id property. The second console log throws an error. How can I get the _id value?
On thinking more about this, the code may actually work. Console log eventually displays nthe id number. The strange thing is the error occurs before the game inserts in server startup. I guess the client started before the server and then reactively aligned with the real data once the server started? This is hard to get my head around coming from traditional web development.
Here is the console output
undefined scoreboard.js?c19ff4a1d16ab47e5473a6e43694b3c42ec1cc22:118
Exception in template helper: TypeError: Cannot read property '_id' of undefined
at Object.Template.game.helpers.Game (http://localhost:3000/client/scoreboard/scoreboard.js?c19ff4a1d16ab47e5473a6e43694b3c42ec1cc22:122:19)
at http://localhost:3000/packages/blaze.js?88aac5d3c26b7576ac55bb3afc5324f465757709:2693:16
at http://localhost:3000/packages/blaze.js?88aac5d3c26b7576ac55bb3afc5324f465757709:1602:16
at Object.Spacebars.call (http://localhost:3000/packages/spacebars.js?3c496d2950151d744a8574297b46d2763a123bdf:169:18)
at Template.game.HTML.DIV.Spacebars.With.HTML.SPAN.class (http://localhost:3000/client/scoreboard/template.scoreboard.js?0ad2de4b00dfdc1e702345d82ba32c20d943ac63:16:22)
at null.<anonymous> (http://localhost:3000/packages/spacebars.js?3c496d2950151d744a8574297b46d2763a123bdf:261:18)
at http://localhost:3000/packages/blaze.js?88aac5d3c26b7576ac55bb3afc5324f465757709:1795:16
at Object.Blaze._withCurrentView (http://localhost:3000/packages/blaze.js?88aac5d3c26b7576ac55bb3afc5324f465757709:2029:12)
at viewAutorun (http://localhost:3000/packages/blaze.js?88aac5d3c26b7576ac55bb3afc5324f465757709:1794:18)
at Tracker.Computation._compute (http://localhost:3000/packages/tracker.js?192a05cc46b867dadbe8bf90dd961f6f8fd1574f:288:36) debug.js:41
game # 0 game time 1395 now 549 scoreboard.js?c19ff4a1d16ab47e5473a6e43694b3c42ec1cc22:148
game # 1 game time 1110 now 549 scoreboard.js?c19ff4a1d16ab47e5473a6e43694b3c42ec1cc22:148
game # 2 game time 1185 now 549 scoreboard.js?c19ff4a1d16ab47e5473a6e43694b3c42ec1cc22:148
game # 3 game time 1260 now 549 scoreboard.js?c19ff4a1d16ab47e5473a6e43694b3c42ec1cc22:148
549, 1, Wed Oct 22 2014 00:00:00 GMT+0930 (CST) scoreboard.js?c19ff4a1d16ab47e5473a6e43694b3c42ec1cc22:157
Object {_id: "scYEdthygZFHgP2G9", court_id: 1, game_date: Wed Oct 22 2014 09:09:50 GMT+0930 (CST), court_name: "Court 1", game_time: "18:30"…} scoreboard.js?c19ff4a1d16ab47e5473a6e43694b3c42ec1cc22:118
scYEdthygZFHgP2G9

Answer 1

I cannot comment on the accepted answer, so I'll put the explaination as to why you see the log error here.
Your code runs just fine, the problem is (and reason for your log error) that you don't take into account that your collection of games isn't populated with any data yet. The first line in your log output reads:
undefined scoreboard.js?c19ff4a1d16ab47e5473a6e43694b3c42ec1cc22:118
which corresponds to
console.log(myGame);
The first time Meteor renders your templates, you simply don't have any data in the Games collection - it's on the wire on the way to your client. Meteor then automatically reruns your templates when data has arrived, explaining the subsequent console outputs.
So basically, the only thing that is wrong with your code at this moment, is the console log that tries to output the _id, since the during the first evaluation there is no game (thus you trying to access the property "_id" of the object "undefined" - the log error message). Remove that line and you should be ready to go!

Answer 2

If the parameter being passed to the function is an array, you can use Array.every. If it's a cursor, you'd need to fetch the results first.
UPDATE
I've just seen your comment. If you're looking for the first game after timenow, just do:
game = Games.findOne({game_minutes: {$gt: timenow}, [ANY OTHER FILTER]}, {sort: {game_minutes: 1}});
I've assumed the collection is called Games, and obviously you need to substitute in any other filter details to get the right set of games to look through, but it should work.

Answer 3

If you can access the game collection, I prefer adding selector and options to your query:
next_game = Games.find(
{
game_minutes: {$gt: timenow}
},
{
sort: {game_minutes: 1},
limit: 1
});
If not, fetch, filter, and then get the minimum one.
new_games = games.fetch().filter(function(game){
return game.game_minutes > timenow;
});
next_game = _.min(new_games, function(game){
return game.game_minutes;
});