I'm trying to write a small service in my angular app which will enable me to pick config parameters specified in global Javascript objects. I don't want to attempt accessing the global config object unless the document is ready (because I cannot guarantee the order in which script elements will be inserted in the HTML).
However, I can't understand why I need the call to $apply for the resolution to actually propagate to the then callback.
myModule.service('GlobalConfigService', ['$q', '$rootScope', function($q, $rootScope) {
var def = $q.defer();
$(document).ready(function() {
def.resolve(MyConfig.val);
$rootScope.$apply();
});
def.promise.then(function () {
console.log('I am called only when $apply() is called. Why?');
});
return def.promise;
}]);
In AngularJS the results of resolve() are propagated asynchronously, inside a $digest cycle, not immediately. This means that callbacks registered with then() will only be called (later) when a digest cycle occurs.
In your code, nothing is causing Angular to enter a digest cycle, so the then() callback is never called. Calling $apply() is one way to cause a digest cycle to run. Another way: add a button with ng-click that does nothing, then click that, it will cause a digest cycle and you should see the results:
<button ng-click="">Force digest by clicking me</button>