Function Returns a Promise, Check Errors

Question

I have a function doSomething() that returns a promise chain, utilizing the Q framework. The contents are similar to something like:

loadDataSet :          


        

Answer 1

You can't throw exceptions inside then as no one will able to catch it. Instead, create a new Q.deferand call reject on it whenever there's an error

loadDataSet : function (params) {
    var deferred = Q.defer()
    Q.fcall(function() {
        //Do Something
    }).then(function(){
       //Do Something Else
       deferred.reject('error message')
    }, deferred.reject)
    return deferred.promise
}

then use it like this

loadDataSet().then(function (data) {
    //ok, got data
}).catch(function (err) {
    //error!
})