General eval worker with timeout in deno.

eval_worker.ts

// eval_worker.ts
// General eval worker with timeout in deno.
/// <reference lib="deno.worker" />
/*
Usage: 
  import {waitForEvalWorkerResponse} from "./eval_worker.ts"
//  await waitForEvalWorkerResponse ( 'javascript code...', 3000 )
  try {
    const source1 = 'await fetch("https://api.github.com/users/octocat").then((response)=>{return response.json()}).catch(err=>{return err})';
    const result1 = await waitForEvalWorkerResponse(source1, 3000);
    console.log(result1); //=>output JSON
    const source2 = 'await (async ()=>{const wait = msec => new Promise(resolve => setTimeout(()=>{resolve()}, msec));console.log("script start");await wait(2000);console.log("2 seconds have passed.");console.log("script end");return 123000+456})()';
    const result2 = await waitForEvalWorkerResponse(source2, 3000);
    console.log(result2); //=>123456
  } catch(err) {
    console.error(err);
  }
*/

const WORKER_PATH: string = "./eval_worker.ts";
const TIMEOUT_MSEC: number = 3000;
const workerURL: URL = new URL(WORKER_PATH, import.meta.url).href;
export async function waitForEvalWorkerResponse(
  source: string,
  timeoutMSec: number = TIMEOUT_MSEC) {
  const worker: Worker = new Worker(workerURL, { type: "module", deno: false });
  return new Promise((resolve, reject) => {
    worker.onmessage = ({ data }) => {
      clearTimeout(timerId);
      worker.terminate();
      if ( data instanceof Error) {
        reject(data);
      } else {
        resolve(data);
      }
    };
    worker.postMessage(source);
    const timerId = setTimeout(() => {
      worker.terminate();
      reject(new Error(`Worker operation timeout (${timeoutMSec} msec)`));
    }, timeoutMSec);
  });
}

self.onmessage = async (e) => {
  const AsyncFunction = async function () {}.constructor;
  await self.postMessage( await AsyncFunction(`'use strict'; return ${e.data}`)() );
  await self.close();
};