Module, setInterval and this..

Hi

I've tried to write a clock module, but it needs to do an internal setInterval to call an internal function. I tried to setInterval(this.tick,1000) but it fails.

I think I found some example code - this defines the function to be called by setInterval in the exported init function - which I think means it will be cloned every time the class is used - which wastes memory a bit.

Is there any way to have a module function that is called by setInterval...?

Thanks

Martin

Hi Martin,

Yes - it should be possible. The issue is probably with what happens to the this variable when called from setInterval. It's a standard JS thing...

You could try something like this:

Clock.prototype.start = function() {
  var me = this;
  setInterval(function() { me.tick(); },1000);
}

This will define a function for each setInterval, but it'll be relatively small.

I'm not sure quite what you're planning, but I wonder how many clock modules a user might have? If it's 1 or 2 it might not matter if the function is duplicated.

Thanks Gordon.... I wasn't sure this was standard JS. I understand it a bit
better now... This business of JS copying out functions seems a bit memory heavy...

The use case for this is just as a general purpose clock. I guess in a typical project there would be just one instance, so it's fine.