There is a well maintained Wasm build of harfbuzz: <https://github.com/harfbuzz/harfbuzzjs https://github.com/harfbuzz/harfbuzzjs> with both OpenType and AAT sh

There is a well maintained Wasm build of harfbuzz: <https://github.com/harfbuzz/harfbuzzjs https://github.com/harfbuzz/harfbuzzjs> with both OpenType and AAT shapers support, which should be enough but you can also provide your own shaper implementation in Wasm yes. We're successfully using Wasm harfbuzz to render text in a web-based design tool with relatively high usage so there should be no issues integrating it :)