what is the difference between deferred.resolve(data); and deferred.resolve(); in angularJS service calls?

Question

I found 2 variation like 1. deferred.resolve(); 2. deferred.resolve(data);

after service response. What is the difference between 2. Which one I have to use strictly.

Answer 1

First scenario:

function getPromise() {
    var deferred = $q.defer();
    deferred.resolve();

    return deferred.promise;
}

getPromise().then(
    function(data) {
        console.log(data); // Output "undefined"
    }
);

Second scenario:

function getPromise() {
    var deferred = $q.defer();
    var data = "hello";
    deferred.resolve(data);

    return deferred.promise;
}

getPromise().then(
    function(data) {
        console.log(data); // Output "'hello'"
    }
);

So it all about on how you resolve the promise, with or without passing information to the function in the resolved promise.