We have a fairly large-ish JS codebase at work and from what I saw so far is that Edge's JS was never a problem. SVG rendering on the other hand is horribly bro

We have a fairly large-ish JS codebase at work and from what I saw so far is that Edge's JS was never a problem. SVG rendering on the other hand is horribly broken currently for some cases. That being said, since our JS is generated, it's purely ES5 since it still has to run on IE9. So maybe the weird cases are in the more modern JS parts we don't use.