1. 下面代码的输出结果是什么

const promise = new Promise((resolve, reject) => {
  console.log(1);
  resolve();
  console.log(2);
});

promise.then(() => {
  console.log(3);
});

console.log(4);

2. 下面代码的输出结果是什么

const promise = new Promise((resolve, reject) => {
  console.log(1);
  setTimeout(() => {
    console.log(2);
    resolve();
    console.log(3);
  });
});

promise.then(() => {
  console.log(4);
});

console.log(5);

3. 下面代码的输出结果是什么

const promise1 = new Promise((resolve, reject) => {
  setTimeout(() => {
    resolve();
  }, 1000);
});
const promise2 = promise1.catch(() => {
  return 2;
});

console.log('promise1', promise1);
console.log('promise2', promise2);

setTimeout(() => {
  console.log('promise1', promise1);
  console.log('promise2', promise2);
}, 2000);

4. 下面代码的输出结果是什么

async function m() {
  const n = await 1;
  console.log(n);
}

m();
console.log(2);

5. 下面代码的输出结果是什么

async function m() {
  const n = await 1;
  console.log(n);
}

(async () => {
  await m();
  console.log(2);
})();

console.log(3);

6. 下面代码的输出结果是什么

async function m1() {
  return 1;
}

async function m2() {
  const n = await m1();
  console.log(n);
  return 2;
}

async function m3() {
  const n = m2();
  console.log(n);
  return 3;
}

m3().then((n) => {
  console.log(n);
});

m3();

console.log(4);

7. 下面代码的输出结果是什么

Promise.resolve(1).then(2).then(Promise.resolve(3)).then(console.log);

8. 下面代码的输出结果是什么

var a;
var b = new Promise((resolve, reject) => {
  console.log('promise1');
  setTimeout(() => {
    resolve();
  }, 1000);
})
  .then(() => {
    console.log('promise2');
  })
  .then(() => {
    console.log('promise3');
  })
  .then(() => {
    console.log('promise4');
  });

a = new Promise(async (resolve, reject) => {
  console.log(a);
  await b;
  console.log(a);
  console.log('after1');
  await a;
  resolve(true);
  console.log('after2');
});

console.log('end');

9. 下面代码的输出结果是什么

async function async1() {
  console.log('async1 start');
  await async2();
  console.log('async1 end');
}
async function async2() {
  console.log('async2');
}

console.log('script start');

setTimeout(function () {
  console.log('setTimeout');
}, 0);

async1();

new Promise(function (resolve) {
  console.log('promise1');
  resolve();
}).then(function () {
  console.log('promise2');
});
console.log('script end');