I experimented 5-6 years ago with a programmable metronome using KnockoutJS and realized quickly how easy it is to cause jitters and unpredictable performance on the main thread. I wish I had come across this post back then!

Although a big contributor for performance issues in my project (and especially OP's) is the amount of UI updates that need to happen in succession (lots of event listeners, css transformations and dom changes)