One thing I'm particularly thrilled about is wasm multi-memory. On first seeing wasm I assumed it was the intent, but for a while it seemed like single memory was going to be the only path forward.
But in the vision of wasm being a lightweight private secure sandbox, being able to give a module more than one bit of memory seems essential. If I have a web handler, I probably need to map in some kind of request object and probably have some other application context that would also be good to map in. Re-crafting a new memory, copying in pieces, seems unideal! Maybe passing these in via function call works in this case, but being able to reference multiple memories of stuff feels like such a powerful option too.
This freedom to combine a bunch of different memories is so so so good to see.
JSPI gets honorable mention, for working to lower impedance of wasm<->js. So many new web apis were being designed with blocking sync interfaces, to make emscripten folks happy, and this was such a necessary proclamation that the runtime would help make introducing that kind of jank unnecessary!
<template>s content is often created with .innerHTML and because the contents are inert they're always on the fast path as parsing doesn't have to create any DOM associations.
