No way to stop a running task inside the callback

[sayantanhore]

Hi,

I am using periodic task in my project. I came across a situation where I needed to stop the task from within the callback. As the API suggests to instantiate a task as below,

var task = new PeriodicTask(delay, callback, [context], [args])

I cannot pass the task task instance into the callback to issue task.stop() inside it.

I suggest a workaround here.

var obj = {};
var task = new PeriodicTask(delay, callback, obj, args);
obj.stop = task.stop.bind(task);

If there is any better approach I would appreciate if you inform me. Otherwise would you like to provide a workaround in the API?

Thanks.
Sayantan ...

[cGuille]

Hello,

If you declare your task variable before defining your task's function, then you can use it inside:

var PeriodicTask = require('periodic-task');

var i = 0;
var task = new PeriodicTask(1000, function () {
    console.log(i++);
    if (i > 3) {
        task.stop();
    }
});
task.run();

Thank you for your feedback!

By the way, as stated in the README, have you considered using async-polling instead of this project?
The above sample could be written like this:

var AsyncPolling = require('async-polling');

var i = 0;
AsyncPolling(function (end) {
    console.log(i++);
    if (i > 3) {
        this.stop();
    }
    end();
}, 1000).run();

[sayantanhore]

Hi,

You are right about the first solution, but my situation is a bit more complicated. I have the callbacks declared before and task is created and run in another function below. Therefore the task is a local variable to that function declared below so somehow I need to pass a this reference to the callback to fire this.stop().

No I have not tried async-polling but will try and if it works (I am sure it will) will replace PeriodicTask with it.

Thanks anyway.

Sayantan ...

[cGuille]

I am going to erase the README of this project, advising to go for async-polling instead. I think it is more relevant to use an asynchrone compliant library in JavaScript, so I prefer to improve async-polling and remove periodic-task.

[sayantanhore]

Ok, would you consider to mention it as deprecated in the NPM repo? I mean here.

[cGuille]

That's a good idea. I'll do this. Thank you for your advice!

[sayantanhore]

You are welcome.