JS, event emitter, callback and asynchrony

Asked Jul 10 '19 at 15:24

Active Jul 10 '19 at 15:28

Viewed 20 times

I have a library written on the callback pattern ...

I want to log in, check errors and continue next, but a misunderstanding of the js asynchronous operation does not give me that ...

let errorInfo = [];

function login() {
    ....
    client.logOn(logOnOptions);

    client.on('error', function (e) { // here callback to check for errors during auth, if it is not handle, the application will throw an exception
        errorInfo.push(e.message);
    })

nextFunction();
}

In this case, if there is an error, JS will start executing the next function nextFunction(), with an empty array ...

How can I stop the transition to the next function until the auth check passes?

edited Jul 10 '19 at 15:28

asked Jul 10 '19 at 15:24

Oliver

1

Should be some *success* event you could use to know when it completes successfully, and then you could use `nextFunction()` in success callback – Isaac Vidrine Jul 10 '19 at 15:27
It's going to execute `nextFunction` immediately. There *might* be an error **later on**. The error won't happen before `nextFunction` is called. – Quentin Jul 10 '19 at 15:29
@IsaacVidrine, I want to wait for filling the array if there are errors and continue – Oliver Jul 10 '19 at 15:30
1

Looks like a good use case for using promises – charlietfl Jul 10 '19 at 15:30
@charlietfl, could you help me to solve my problem? – Oliver Jul 10 '19 at 15:38
Not enough shown to know how `logOn` works. Read up on how to use promises – charlietfl Jul 10 '19 at 15:39
@charlietfl, i try but callback "function(e)" handle when there is an error – Oliver Jul 10 '19 at 16:12

JS, event emitter, callback and asynchrony

0 Answers0