Promise.js

Promise.js

(async () => {

  let promise1 = new Promise((resolve, eject) => {
    resolve('YES');
  });


  promise1.then( r => console.log(r) ); // YES
  console.log(await promise1); // YES


  const test2 = async () => {
    return await promise1;
  };
  console.log(test2()); // Promise
  test2().then( r => console.log(r) ); // YES
  console.log(await test2()); // YES


  const test3 = async () => {
    const text = await promise1;
    return text + ' ' + text;
  };
  console.log(test3()); // Promise
  test3().then( r => console.log(r) ); // YES YES
  console.log(await test3()); // YES YES


  const concat = (val1, val2) => val1 + ' ' + val2;
  const test4 = async () => {
    const text = await promise1;
    return concat(text, text);
  };
  console.log(test4()); // Promise
  test4().then( r => console.log(r) ); // YES YES
  console.log(await test4()); // YES YES

  console.log(concat(await promise1, await promise1)); // YES YES
  console.log(concat(promise1, promise1)); // [object Promise] [object Promise]

})();