使用deferred和promise循环ajax调用

Question

I am new to jquery $.Deferred and it seems that I cannot understand a whole bunch of stuffs regarding async processing.

Let say I wanna loop through usernames and login them, process something, and logout(this might not be necessary to include in the this question).

If I have this 2 user/pass combinations, I want to loop through them, login them and do necessary actions.

[{"username":"user1","password":"HardToKnow"},
 {"username":"user2","password":"HardToKnow"}]

And I have created this function based on what I read, although I am not certain on how this works.

function login(user, pass) {
    var d = $.Deferred();
    $.post(
        'http://www.domain.com/login',
        {
            user: user,
            passwrd: pass
        }
    ).done(function(s){
            d.resolve(s);
    }).fail(d.reject);

    return d.promise();
}

The above function is obviously for login, and now I will have another function that must have another async request.

function setTodo(user,pass) {
    return login(user,pass)
           .pipe(function(s){
                if (s.indexOf('<li class="greeting">Hello <span>' + user + '</span></li>')) {
                    return $.post().....?

                }
                return set(usr, pw);
           });
}

That function above, although not complete, that i just my idea, will try to Set a todo and later another function will be called to submit or to finalize the todo

function submit(user, pass) {
     return setTodo(user, pass)
            .pipe(function(s){
            // another $.post() here...
     }
}

Question, am I doing it correctly? the deferred? How do I loop through the login credentials? I tried using $.each and ajax request them, but as expected they executed at the same time because it is async.

Answer 1

Yes. Overall you are doing it right, but note that pipe is being deprecated in favor of then .

Here is the documentation of then .