How to update several nodes in firebase using then - angularjs

Question

I want to update several nodes in firebase since data is denormalized. So when updating each node have to wait until the previous updates is success.
So I have something below (what I currently use), you can see it is not readable if getting more nodes to update.
if(foo1) {
firebaseRef.update(data, function(error) {
if(error){
console.log(error);
} else {
firebaseRef.update(data, function(error){
if(error){
console.log(error);
}else{
//Update Another
};
});
};
});
};
So any idea how to use .then in angularFire or pure firebase js api something like this.
firebaseRef().then(function(){
return doSomething;
}).then(function(){
return doSomething;
}).then(function(){
return doSomething;
}).then(function(){
return doSomething;
});

Answer 1

There are no futures in Firebase or AngularFire, at present. So you would need to use a decorator/wrapper strategy.
jQuery:
function update(ref, data) {
$.Deferred(function(def) {
ref.update(data, function(err) {
if( err ) def.reject(err);
else def.resolve();
});
});
}
var fb = new Firebase(URL);
update(fb.child('path1'), 'foo')
.then(update.bind(null, fb.child('path2'), 'bar'))
.then(update.bind(null, fb.child('path3'), 'foobar'))
.done(function() { console.log('yay!'); });
Angular:
angular.service('update', function($q, $timeout) {
return function(ref, data) {
var def = $q.defer();
ref.update(data, function(err) {
if( err ) def.reject(err);
else def.resolve();
});
return def.promise;
}
});
angular.controller('ctrl', function(update) {
var fb = new Firebase(URL);
update(fb.child('path1'), 'foo')
.then(update.bind(null, fb.child('path2'), 'bar'))
.then(update.bind(null, fb.child('path3'), 'foobar'))
.done(function() { console.log('yay!'); });
});
Bind polyfill (rather handy with Futures): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind#Compatibility
You could also pull this off without using .bind if you like this syntax better:
function updateHandler(ref, data) {
return function() {
$.Deferred(function(def) {
ref.update(data, function(err) {
if( err ) def.reject(err);
else def.resolve();
});
});
}
}
var fb = new Firebase(URL);
updateHandler(fb.child('path1'), 'foo')()
.then(updateHandler(fb.child('path2'), 'bar'))
.then(updateHandler(fb.child('path3'), 'foobar'))
.done(function() { console.log('yay!'); });