This is a very WIP proof-of-concept host for WCLAP (Web CLAP) plugins. Although this host is browser-based, a similar approach could be used for non-web contexts.
There are three layers:
The source for this is in clap-host/, with the main entry point being clapModule() from clap-module.mjs. This takes the WebAssembly Module for a CLAP plugin, and lets you query/create plugin instances.
Rather than wrap the CLAP API in any way, clap-interface.mjs makes it easy to define and read/write C structs in the WebAssembly memory, call functions (from function pointers), proxy your own JS functions as function pointers, and add CLAP extensions. The core CLAP types/extensions are already defined.
This fetches/compiles a .wasm, and uses the Module to construct an AudioWorkletProcessor. This processor uses the CLAP host helpers (above) to configure/activate the plugin and process audio blocks.
The AudioWorkletNode has proxy methods added to it, which asynchronously scan/update parameters and save/load state, by posting messages across to the processor. It also receives events from the processor (such as "state marked dirty").
They also use the WIP clap.web/1 draft extension, which (if supported) opens a web-page and passes arbitrary messages between the web-page and the plugin, allowing plugins to present a web-based UI. Since this host is running in the browser, this web-view is loaded in an <iframe>.
WCLAP bundles might contain multiple resources, in which case they should be served as .tar.gz archives. The main page registers a Service Worker which can fetch these bundles, extract them, and serve them as if they were individual resources.