Why am I getting undefined when returning data from this Promise?

Question

data below is being returned undefined:

function selectSearchedTicker(ticker, load) {
    var deferred = $q.defer();

    GetTickersFactory.getTickers('searched', load).then(function(data) {
        console.log('data',data);
        var tempTickers = GetTickersFactory.returnSearchedTickers();
        $rootScope.$emit("select.searched.ticker", tempTickers);
        deferred.resolve();
    });

    return deferred.promise;
}

This is the GetTickersFactory.getTickers function:

function getTickers(type, load, searchedTicker, cached) {
    type = type || 'portfolio';
    load = load || '';
    searchedTicker = searchedTicker || {};

    var deferred = $q.defer(),
        promise;

    if (cached) portfolioCached = cached;

    //other code remains same
    tickersPane = ScopeFactory.getScope('tickersPanel');

    switch (type) {
        case 'searched':
            return ApiFactory.getTickers(null, load).then(function(data) {

                //renderTickers just does logic, no more API call
                searchedTickers.that = renderTickers(data.data.tickers, searchedTicker, 'searched');
                promise = searchedTickers.that;
                console.log('promise',promise); // <-- there is data here
                deferred.resolve(promise);
                // return returnData(searchedTickers.that);
            });
            break; // <-- after hitting this break, chrome tools hits the Angular code
        //...
    }

    return deferred.promise; // <- also tried return promise

    // other functions...
}

You can see above promise = searchedTickers.that; when I log that, I see the data I want returned inside it. However it never makes it back to my original selectSearchedTicker function.

---

Update: Added this code which precedes everything, I had to make a promise chain, because I need to wait till TickersSelectFactory.selectSearchedTicker is called and the results of those actions are finished, before I call the 2 $emit's.

TickersSelectFactory.selectSearchedTicker(fullTicker.ticker, selectTickerUrl).then(function(res) {
    console.log('selectSearchedTicker promise returned');
    $rootScope.$emit("clear.tags.array");
    $rootScope.$emit("search.ticker.clicked", fullTicker);
});

Originally it looked like this and was giving me problems:

TickersSelectFactory.selectSearchedTicker(fullTicker.ticker, selectTickerUrl);
$rootScope.$emit("clear.tags.array");
$rootScope.$emit("search.ticker.clicked", fullTicker);

Answer 1

The correct resolution to your problem is to use the built-in chaining that .then() provides, and do away with the extraneous $q.defer() object:

switch (type) {
    case 'searched':
        return ApiFactory.getTickers(null, load).then(function(data) {
            searchedTickers.that = renderTickers(data.data.tickers, searchedTicker, 'searched');
            return searchedTickers.that;
        });
    ...
}

similarly in your first function:

function selectSearchedTicker(ticker, load) {
    return GetTickersFactory.getTickers('searched', load).then(function(data) {
        console.log('data',data);
        var tempTickers = GetTickersFactory.returnSearchedTickers();
        $rootScope.$emit("select.searched.ticker", tempTickers);
        return tempTickers;
    });
}

(note the new return at the start of the function, that ensures that the caller of this function correctly receives a Promise)

Answer 2

Figured it out, I was returning my ApiFactory call, which ended my promise chain, before I was able to add the data into the promise to resolve back upwards.

// return ApiFactory.getTickers(null, load).then(function(data) {
ApiFactory.getTickers(null, load).then(function(data) {

---

case 'searched':
    // With the return below, the code never got in to set the promise up and resolve it
    // return ApiFactory.getTickers(null, load).then(function(data) {
    ApiFactory.getTickers(null, load).then(function(data) {
        searchedTickers.that = renderTickers(data.data.tickers, searchedTicker, 'searched');
        promise = searchedTickers.that;
        console.log('searched promise',promise);
        deferred.resolve(promise);
    });
    break;