Making Teleporting Smarter

(This is a republish of an article posted at SpiderMonkey.dev for my own archiving purposes) Recently I got to land a patch which touches a cool optimization, that I had to really grok. As a result, I wrote a huge commit message . I’d like to expand that message a touch here and turn it into a nice blog post. This post assumes roughly that you understand how Shapes work in the JavaScript object…