Flash games and animations often had a lot of static assets, like sound, bitmap images, or fonts. You could data-uri all that in your html file, too, but with all the base64 overhead it might be a good idea to compress everything afterwards (e.g. SingleFileZ, see my other comment). Of course only if file shipment is an issue for you, otherwise relying on your server's gzip compression might be enough.

Try xz compression and put in a blob and then and put in wasm (C or rust for best performance). You can inline the wasm in single html file along with js and css. At load time, in wasm, you can decompress and instantiate the elements/objects/records from parsing the blob. You can keep in wasm or copy/move to js land. Sounds like a lot but it's pretty easy.