javascript循环中断

Question

I know i should know how to do this but some how it escapes me. I need to exit the loop here once I have a match. Why does this not work?

ubot.registry.queue.each(function (dj, idx) {
    console.log(idx);
    var user = ubot.registry.users.get(dj.userid);
    console.log(user.name);
    console.log(rm_user)
    if(user.name == rm_user) {
        console.log(dj.userid);
        return; // not exiting loop here 
        /*
        if(!ubot.dj_timeout) {
            ubot.remUserFromQueue(user);
            return true;
        } else {
            console.log(ubot.dj_timout);
        }
        */
    }
});

Answer 1

Here's a generic solution since you haven't given us specifics on the code you're running.

It doesn't break the loop. Instead it prevents the code inside the function from running once a flag is set.

var flag = false;

ubot.registry.queue.each(function (dj, idx) {
    if( !flag )
        var user = ubot.registry.users.get(dj.userid);
        if(user.name == rm_user) {
            console.log(dj.userid);
            flag = true;
            // rest of the code
        }
    }
});

---

"Why does this not work?"

You're returning undefined , but functions always return undefined unless a specific return value is provided. So by doing return; you're not doing anything different than the function would do anyway.

Answer 2

You don't say what framework you're using, but I'm going to take a wild guess and suppose that you're using Prototype's Enumerable.each . If so, you can exit the "loop" by using this statement:

throw $break;

which throws a custom exception that the each method understands as meaning "break out of the 'loop'".

Answer 3

如果您可以访问each() ，那么也许您就可以访问some()或any()之类的东西-即each()的可短路版本。