workerize-loader-wp5/src/rpc-worker-loader.js

Automatically move a module into a Web Worker (Webpack loader)

/* global __webpack_exports__ */

function workerSetup() {
  addEventListener("message", e => {
    let { type, method, id, params } = e.data,
      f,
      p;
    if (type === "RPC" && method) {
      if ((f = __webpack_exports__[method])) {
        p = Promise.resolve().then(() => f.apply(__webpack_exports__, params));
      } else {
        p = Promise.reject("No such method");
      }
      p.then(result => {
        postMessage({ type: "RPC", id, result });
      }).catch(e => {
        let message;
        try {
          message = e.message.toString();
        } catch (ex) {
          message = null;
        }
        let error = { message };
        if (e.stack) {
          error.stack = e.stack;
          error.name = e.name;
        }
        if (e.status) {
          error.status = e.status;
          error.responseJson = e.responseJson;
        }
        postMessage({ type: "RPC", id, error });
      });
    }
  });
  postMessage({ type: "RPC", method: "ready" });
}

const workerScript =
  "\n" +
  Function.prototype.toString
    .call(workerSetup)
    .replace(/(^.*\{|\}.*$|\n\s*)/g, "");

export default function rpcWorkerLoader(content, sourceMap) {
  const callback = this.async();
  callback(null, content + workerScript, sourceMap);
}