Is async await truly non-blocking in the browser?

by

await p schedules execution of the rest of your function when promise p resolves. That’s all.

async lets you use await. That’s (almost) all it does (It also wraps your result in a promise).

Together they make non-blocking code read like simpler blocking code. They don’t unblock code.

For a responsive UI, offload CPU-intensive work to a worker thread, and pass messages to it:

async function brutePrime(n) {
  function work({data}) {
    while (true) {
      let d = 2;
      for (; d < data; d++) {
        if (data % d == 0) break;
      }
      if (d == data) return self.postMessage(data);
      data++;
    }
  }

  let b = new Blob(["onmessage =" + work.toString()], {type: "text/javascript"});
  let worker = new Worker(URL.createObjectURL(b));
  worker.postMessage(n); 
  return await new Promise(resolve => worker.onmessage = e => resolve(e.data));
}

(async () => {
  let n = 700000000;
  for (let i = 0; i < 10; i++) {
    console.log(n = await brutePrime(n + 1));
  }
})().catch(e => console.log(e));

More Related Contents:

  1. async/await always returns promise
  2. How to “await” for a callback to return?
  3. Is it an anti-pattern to use async/await inside of a new Promise() constructor?
  4. Combination of async function + await + setTimeout
  5. Use async await with Array.map
  6. Correct Try…Catch Syntax Using Async/Await
  7. Waiting for more than one concurrent await operation
  8. How can I use async/await at the top level?
  9. How to return values from async functions using async-await from function? [duplicate]
  10. Using async/await with a forEach loop
  11. Why is my infinite loop blocking when it is in an async function? [duplicate]
  12. What is the difference between JavaScript promises and async await?
  13. How not to forget using await everywhere in Javascript?
  14. Is there a way to wrap an await/async try/catch block to every function?
  15. How to use ES8 async/await with streams?
  16. Async/Await inside Array#map()
  17. How to return an Ajax result using async/await? [duplicate]
  18. Understanding async/await on NodeJS
  19. using async await and .then together
  20. How to implement a pseudo blocking async queue in JS/TS?
  21. ES8 Immediately invoked async function expression
  22. Async function without await in JavaScript
  23. Use Async/Await with Axios in React.js
  24. What are asynchronous functions in JavaScript? What is “async” and “await” in JavaScript?
  25. How does javascript async/await actually work?
  26. Does an async function always need to be called with await?
  27. Await an iterative function without delimiter in JS
  28. Using “await” inside non-async function
  29. ASYNC / AWAIT SyntaxError: await is only valid in async functions and the top level bodies of modules
  30. JS async/await – why does await need async?

Leave a Comment