使用Async方式处理接受Promise结果可以省去then接收结果，更为方便

Promise.all和Async-Await

const bcrypt = require('bcrypt');

const NUM_SALT_ROUNDS = 8;

async function test() {
  const pws = ["passwd", "passwd2", "passed3"];
  const promises = pws.map(pw => bcrypt.hash(pw, NUM_SALT_ROUNDS));
  const result = await Promise.all(promises);
  console.log(result);
}


function test2() {
  const pws = ["passwd", "passwd2", "passed3"];
  const promises = pws.map(pw => bcrypt.hash(pw, NUM_SALT_ROUNDS));
  Promise.all(promises).then(result => {
    console.log(result);
  });
}

test();
test2();