gulp run sequence after promise resolve

问题:

Main task is provided to user availability to put login and password before each run task. So i try to use promises, but in such case my sequence doesn`t start because task finished when promise resolved.

export default function() {
    var loginPromise = new Promise((resolve, reject) => {
        inquirer.prompt(config.loginQuestions).then(answer => {
            if (!(answer.login.length && answer.password.length)) {
                reject('loginError')
            } else {
                resolve(answer)
            }
        });
    });
    return loginPromise;
};

And task

    import login from '../util/login';
    gulp.task('sassComponents', function() {
        return login().then(function(answer) {
           console.log('started')  //This code executed and i see console
           return gulp.src(conf.sassPath)
            .pipe(sourcemaps.init())
            .pipe(sass())
            .pipe(autoprefixer(config.autoprefixer))
            .pipe(sourcemaps.write())
            .pipe(gulp.dest(function(file) { 
                 return destPath(file)   // destPath doesn`t start
             })) 
        })
    });

So login() is execution of first function. Then console appear but destPath doesn`t start. Maybe you have any idea how to fix it?