I have an AngularJS service that I want to initialize with some asynchronous data. Something like this:
myModule.service('MyService', function($http) {
var myData = null;
$http.get('data.json').success(function (data) {
myData = data;
});
return {
setData: function (data) {
myData = data;
},
doStuff: function () {
return myData.getSomeData();
}
};
});
Obviously this won't work because if something tries to call doStuff() before myData gets back I will get a null pointer exception. As far as I can tell from reading some of the other questions asked here and here I have a few options, but none of them seem very clean (perhaps I am missing something):
Setup Service with "run"
When setting up my app do this:
myApp.run(function ($http, MyService) {
$http.get('data.json').success(function (data) {
MyService.setData(data);
});
});
Then my service would look like this:
myModule.service('MyService', function() {
var myData = null;
return {
setData: function (data) {
myData = data;
},
doStuff: function () {
return myData.getSomeData();
}
};
});
This works some of the time but if the asynchronous data happens to take longer than it takes for everything to get initialized I get a null pointer exception when I call doStuff()
Use promise objects
This would probably work. The only downside it everywhere I call MyService I will have to know that doStuff() returns a promise and all the code will have to us then to interact with the promise. I would rather just wait until myData is back before loading the my application.
Manual Bootstrap
angular.element(document).ready(function() {
$.getJSON("data.json", function (data) {
// can't initialize the data here because the service doesn't exist yet
angular.bootstrap(document);
// too late to initialize here because something may have already
// tried to call doStuff() and would have got a null pointer exception
});
});
Global Javascript Var I could send my JSON directly to a global Javascript variable:
HTML:
<script type="text/javascript" src="data.js"></script>
data.js:
var dataForMyService = {
// myData here
};
Then it would be available when initializing MyService:
myModule.service('MyService', function() {
var myData = dataForMyService;
return {
doStuff: function () {
return myData.getSomeData();
}
};
});
This would work too, but then I have a global javascript variable which smells bad.
Are these my only options? Are one of these options better than the others? I know this is a pretty long question, but I wanted to show that I have tried to explore all my options. Any guidance would greatly be appreciated.