How to deal with async requests in Marionette? - marionette

Question

I am trying to fill in an ItemView in Marionette with the combined results of 2 API requests.
this.standings = App.request('collection:currentStandings');
this.userInfo = App.request('model:userInfo');
this.standings.each(function(s) {
if (s.currentUser) {
s.set('alias', this.userInfo.alias);
s.set('imageURL', this.userInfo.imageURL);
}
});
userInfoView = new LeagueBar.UserInfo({ collection: this.standings });
The problem is, the combination never happens because the requests have not been fulfilled before I try to combine them.
I know I probably need to add a promise for each request, but I haven't been able to find a clean way to do it. I could make 'collection:currentStandings' and 'model:userInfo' return promises, however, they are currently used in many other parts of the code, so I would have to go back and add .then()s and .done()s all over the code base where they weren't required before.
Any ideas or suggestions?
EDIT:
I have currently solved this in a less-than-ideal way: I created a template/view for the alias and a template/view for the imageURL and kept the template/view for the standings info. This doesn't seem like the best way and I'm interested to know the right way to solve this problem.
here are the two requests I am trying to combine:
Models.CurrentStandings = App.Collection.extend({
model: Models.PlayerStandings,
url: function() { return 'leagues/' + App.state.currentLeague + '/standings'; },
parse: function(standings) {
return _.map(standings, function(s) {
if (s.memberId == App.user.id)
s.currentUser = true;
return s;
});
}
});
App.reqres.setHandler('collection:currentStandings', function() {
weekStandings = new Models.CurrentStandings();
weekStandings.fetch({ success: function(data){ console.log(data); }});
return weekStandings;
});
Models.UserInfo = App.Model.extend({
url: 'users/me'
});
App.reqres.setHandler('model:userInfo', function(options) {
myuser = new Models.UserInfo();
myuser.fetch(options);
return myuser;
});

Answer 1

There are 2 solutions which based on your dependencies among views can be selected:
You can create views which are handling 'change' event of Models.UserInfo and when the data is ready (Change/Reset event raised) re-render the content. It is probably your solution.
If you are looking for a solution which should not create instance of LeageBar.UserInfo until both Models.CurrentStanding and Models.UserInfo are ready, you have to return the result of fetch function, so you may remove calling fetch from setHandlers and use them as following:
this.standings = App.request('collection:currentStandings');
this.userInfo = App.request('model:userInfo');
var that=this;
that.standings.fetch().done(function(){
that.userInfo.fetch().done(function(){
that.standings.each(function(s) {
if (s.currentUser) {
//....
}
});
userInfoView = new LeagueBar.UserInfo({ collection: that.standings });
});