JS bindings don't work when there are dependencies on wasm bindgen

Problem

I ran into an issue while using diplomat to create js bindings for a library I'm working on. The library has dependencies which themselves seem to depend on wasm bindgen. The generated wasm expects interfaces provided by wasm_bindgen in the form of

[TypeError: WebAssembly.instantiate(): Import #0 module="__wbindgen_placeholder__" error: module is not an object or function]

I created a minimal reproducible example here: https://github.com/jcrist1/diplomat-dbg/tree/6649bacd8e004f82814510774acde572625be891/wasm_bindgen

Workaround

I found a relatively easy workaround, but did have to spend a lot of time debugging to figure it out. Just needed to run wasm-bindgen on the generated wasm, use that for the module, and add a line to imports in diplomat-wasm.mjs:

import cfg from "../diplomat.config.mjs";
import { readString8 } from "./diplomat-runtime.mjs";
import * as dbg_bg from "./dbg_bg.js";  // <- this line

let wasm;
const imports = {
  "./dbg_bg.js": dbg_bg, //  <-- and this line
  env: {
    diplomat_console_debug_js(ptr, len) {
      console.debug(readString8(wasm, ptr, len));
    },
    diplomat_console_error_js(ptr, len) {
      console.error(readString8(wasm, ptr, len));
    },
    diplomat_console_info_js(ptr, len) {
      console.info(readString8(wasm, ptr, len));
    },
    diplomat_console_log_js(ptr, len) {
      console.log(readString8(wasm, ptr, len));
    },
    diplomat_console_warn_js(ptr, len) {
      console.warn(readString8(wasm, ptr, len));
    },
    diplomat_throw_error_js(ptr, len) {
      throw new Error(readString8(wasm, ptr, len));
    },
  },
};

Proposals:

wasm-bindgen seems pretty embedded in a lot of crates that support wasm, and is a big part of the rust wasm ecosystem, so some kind of support would be nice, but it feels like directly integrating with wasm-bindgen doesn't seem like it aligns with diplomat's goals. I came up with

Add documentation on how to use wasm bindgen and manually modify the generated files when libraries depend on it
Require any extra imports be specified in diplomat.config.mjs, and include their use in the generated diplomat-wasm.mjs, but don't automatically generate bindgen (i.e. generating {lib}_bg.js) (and document using wasm-bindgen)
Directly integrate wasm-bindgen, as part of some kind of diplomat tool

I hope 1. would not be too much, but I would prefer 2. I don't think 3. makes sense as dipomat doesn't seem to do really do anything to the compile step.

rust-diplomat / diplomat