terser-playground

I was looking about for an easy way to check minified sizes on some es-after-5 code, and behold, there's a @Rich-Harris project for that! I wanted to try out svelte v3, so I ported this, and apart from being a little var-y in this case, it's really slick! The only weird-ish thing is not being able to observe a value to trigger some code. I tried to follow the RFCs, but I missed a bit there in the middle. Was there ever a proposal along the lines of ? That may be a bit too silly/magical, but it's a fairly common pattern for observers in lots of my code. You could even go crazy and allow for old values to be collected in a second param and subscriptions handled by destructure on the first. But again, that may peg the silly scale. I also added KiB outputs for plain text and gzip at level 6 for both input and output.