Meteor + Microsoft Browsers = :´(

I was just testing a Meteor app with different operating systems and browsers, and it’s completely unusable on IE Edge / Windows 10.

The laptop isn’t brand new, but it does have a dual core Intel CPU with 6Gb of memory. On Chrome and Firefox the app is snappy as usual, but with IE, just opening a form can take 2-3 seconds. Subscriptions load approximately 5x slower than on Chrome.

The app I’m testing is just “classic” Meteor with ViewModel sugaring on top of Blaze.

Anybody else ever notice this type of behavior with Microsoft browsers and Meteor? Is Microsoft’s Javascript engine that bad?

I ran the same actions and profiled them on Edge and Chrome.

Tracker’s ._runFlush took 3858ms of CPU time on Edge and 1100ms on Chrome.

Using a transition effect by webtempest:animate seems to be causing a lot of unnecessary recalculation of styles all over the page on Edge, which seems to be the biggest culprit.

Also, using a lot of ViewModel’s class-bindings seems to be causing a lot of style recalculations, which Edge apparently handles really badly.