Update scheduler.ts

[pfulop]

There was a bug if pollInterval was created scheduler had timer set. However after deleting the interval and creating new one with same interval value, the scheduler wouldn't reschedule (the scheduler cleared the timer since it had empty list in intervalQueries). In this case any more intervalQueries with same interval would not simply run.

TODO:

• Update CHANGELOG.md with your change
• [ x] Make sure all of the significant new logic is covered by tests
• [ x] Rebase your changes on master so that they can be merged easily
• [ x] Make sure all tests and linter rules pass

[apollo-cla]

@pfulop: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Meteor Contributor Agreement here: https://contribute.meteor.com/

[Poincare]

Thanks for catching this!

I think your solution to the issue is correct; could you write a test case that tests this behavior? It would probably go in test/scheduler.ts and should test the length of the list within intervalQueries as well as whether or not the correct polling query is fired.

[pfulop]

My first PR so I hope I've got it right.

[stubailo]

@pfulop can you sign the contributor agreement, so we can accept the PR? Looking really great so far!

[BLamy]

I can confirm that this fixed the issue I was having, Thanks pfulop.

[stubailo]

Going to merge this via #568