Make angular.forEach wait for promise after going to next object

Question

I have a list of objects. The objects are passed to a deferred function. I want to call the function with the next object only after the previous call is resolved. Is there

Answer 1

Yes you can use angular.forEach to achieve this.

Here is an example (assuming objects is an array):

// Define the initial promise
var sequence = $q.defer();
sequence.resolve();
sequence = sequence.promise;

angular.forEach(objects, function(val,key){
    sequence = sequence.then(function() {
        return doSomething(val);
    });
});

---

Here is how this can be done using array.reduce, similar to @friend00's answer (assuming objects is an array):

objects.reduce(function(p, val) {
    // The initial promise object
    if(p.then === undefined) {
        p.resolve(); 
        p = p.promise;
    }
    return p.then(function() {
        return doSomething(val);
    });
}, $q.defer());