Promise4.js

const testPromise = (num,sec) => {
  const random = Math.round(Math.random() * 10); //ランダムで0〜9の数値を返す
  return new Promise((resolve, reject) => {
        setTimeout(() => { 
            console.log(num + ":  random is " + random);
            if (random === 3) reject("random is three"); 
            resolve("random is " + random)
        },sec);
    })
}

const p1 = testPromise(1, 3000);
const p2 = console.log("Not Promise Method");
const p3 = testPromise(2,10);
const p4 = testPromise(3,2);

Promise.all([p1, p2, p3, p4])
.then((results) => results.forEach((result) => console.log("Success: " + result)))
.catch((err) => console.log("Error: " + err))