parcel-transformer-wasm-module-sync/dist/index.js

Support synchronous WASM module imports in Parcel 2

import { Transformer } from '@parcel/plugin';
import dedent from 'dedent';

export default new Transformer({
  async transform({ asset }) {
    const wasmBinary = await asset.getBuffer();
    const wasmModule = new WebAssembly.Module(wasmBinary);

    const importedModules = [
      ...new Set(WebAssembly.Module.imports(wasmModule).map((i) => i.module)),
    ];
    const imports = [
      '{',
      ...importedModules.map((m) => `${JSON.stringify(m)}: require('${m}'), `),
      '}',
    ].join('');

    const wasmEncoded = wasmBinary.toString('base64');
    const wasmShim = dedent`
      const wasmBase64 = "${wasmEncoded}";
      const wasmBinary = Uint8Array.from(atob(wasmBase64), c => c.charCodeAt(0));
      const wasmModule = new WebAssembly.Module(wasmBinary);
      const wasmInstance = new WebAssembly.Instance(wasmModule, ${imports}); 
      module.exports = wasmInstance.exports;
    `;

    asset.type = 'js';
    asset.bundleBehavior = 'isolated';
    asset.setCode(wasmShim);
    return [asset];
  },
});