fight-for-bat

本项目为饥人谷系统班大厂冲刺课程，不接受转载。如需了解合作咨询vx: xiedaimala03

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Week 1

以下内容视频讲解在这里

Promise 相关问题

1. 聊一聊Promise的原理
2. 使用Promise封装Ajax
3. Promise.all、Promise.allSettled、Promise.race、Promise.any、Promise.resolve、Promise.reject 分别有什么用？
4. 手写Promise.all、Promise.race、Promise.allSettled、Promise.any、Promise.resolve、Promise.reject
5. 并发请求限制数量手写代码
6. 手写代码实现Promisify
7. 说一说宏任务微任务的处理方式
8. 手写一个Promise

代码输出题

1. 代码输出什么

   setTimeout(() => console.log(1), 0);
   new Promise(resolve => {
    resolve();
    console.log(2);
   }).then(() => {
     console.log(3);
   });
   console.log(4);
   

2. 输出什么

new Promise(function f1(resolve){
  console.log(1);
  setTimeout(function f2() {
    console.log(2);
  });
  resolve(1);
}).then(function f3(res) {
  console.log(3);
})

setTimeout(function f4() {
  console.log(4);
})

console.log(5);

1. 输出什么

setTimeout(function f1() { 
  console.log(1) 
})

new Promise(function f2(resolve) {
  resolve()
  console.log(2)
}).then(function f3() {
  console.log(3)
  Promise.resolve().then(function f4() {
    console.log(4)
  }).then(function f5() {
    Promise.resolve().then(function f6() {
      console.log(5)
    })
  })
})

console.log(6)

1. 输出什么

console.log(1)
setTimeout(function f1(){
  console.log(2)
  Promise.resolve().then(function f2() {
      console.log(3)
      setTimeout(function f3() {
        console.log(4)
      })
  }).then(function f4() {
      console.log(5)
  })
}, 0)
console.log(6)

1. 输出什么

const pro = new Promise(function f1(resolve) {
  const innerpro = new Promise(function f2(resolve) {
    setTimeout(function f3(){
      resolve(1);
    }, 0);
    console.log(2);
    resolve(3);
  });
  innerpro.then(function f4(res) {console.log(res)} );
  resolve(4);
  console.log(5);
})
pro.then(function f5(res) { console.log(res) });
console.log(6); 

1. 输出什么

async function async1() {
  console.log('async1 start');
  await async2();
  console.log('async1 end');
}
async function async2() {
  console.log('async2 start');
  return new Promise((resolve, reject) => {
    resolve();
    console.log('async2 promise');
  })
}
console.log('script start');
setTimeout(function() {
  console.log('setTimeout');
}, 0);  
async1();
new Promise(function(resolve) {
  console.log('promise1');
  resolve();
}).then(function() {
  console.log('promise2');
}).then(function() {
  console.log('promise3');
});
console.log('script end');

1. 输出什么

new Promise((resolve, reject) => {
  reject('error')
}).then(()=> {
  console.log('ok 1')
}, (err) => {
  console.log('error 1: ' +  err)
}).then(() => {
  console.log('ok 2')
}, (err) => {
  console.log('error 2: ' + err)
}).catch(err => {
  console.log('catch 1: ' + err)
})