upstream/emscripten/src/wasm_worker.js

var wwParams;

/**
 * Called once the initial message has been received from the creating thread.
 * The `props` object is property bag sent via postMessage to create the worker.
 *
 * This function is called both in normal wasm workers and in audio worklets.
 */
function startWasmWorker(props) {
#if RUNTIME_DEBUG
  dbg('startWasmWorker', props);
#endif
  wwParams = props;
  wasmMemory = props.wasmMemory;
  updateMemoryViews();
#if MINIMAL_RUNTIME
  Module ||= {};
  Module['wasm'] = props.wasm;
  loadModule()
#else
  wasmModule = props.wasm;
#if MODULARIZE == 'instance'
  init();
#else
  createWasm();
  run();
#endif
#endif
  // Drop now unneeded references to from the Module object in this Worker,
  // these are not needed anymore.
  props.wasm = props.wasmMemory = 0;
}

#if AUDIO_WORKLET
if (ENVIRONMENT_IS_WASM_WORKER && !ENVIRONMENT_IS_AUDIO_WORKLET) {
#else
if (ENVIRONMENT_IS_WASM_WORKER) {
#endif
#if RUNTIME_DEBUG
  dbg('wasm worker starting ...');
#endif

#if ENVIRONMENT_MAY_BE_NODE
// Node.js support
if (ENVIRONMENT_IS_NODE) {
  // Weak map of handle functions to their wrapper. Used to implement
  // addEventListener/removeEventListener.
  var wrappedHandlers = new WeakMap();
  /** @suppress {checkTypes} */
  globalThis.onmessage = null;
  function wrapMsgHandler(h) {
    var f = wrappedHandlers.get(h)
    if (!f) {
      f = (msg) => h({data: msg});
      wrappedHandlers.set(h, f);
    }
    return f;
  }

  Object.assign(globalThis, {
    addEventListener: (name, handler) => parentPort['on'](name, wrapMsgHandler(handler)),
    removeEventListener: (name, handler) => parentPort['off'](name, wrapMsgHandler(handler)),
  });
}
#endif // ENVIRONMENT_MAY_BE_NODE

onmessage = (d) => {
  // The first message sent to the Worker is always the bootstrap message.
  // Drop this message listener, it served its purpose of bootstrapping
  // the Wasm Module load, and is no longer needed. Let user code register
  // any desired message handlers from now on.
  /** @suppress {checkTypes} */
  onmessage = null;
#if RUNTIME_DEBUG
  dbg('wasm worker initial onmessage');
#endif
  startWasmWorker(d.data);
}

}