es6 promise

function p(flag){
  return new Promise((resolve , reject)=>{
    if(flag){
      resolve('ok');
    }else{
      reject('no');
    }
  });
}

function a(){
  alert('a');
}

function b(){
  alert('b');
}

p(true).then((msg)=>{
  alert(msg);
},(err)=>{
  alert(err);
}).then(a).then(b)

 

var p = new Promise((resolve, reject) => {
  console.log('创建Promise 实例');
  $.getScript('https://ss0.bdstatic.com/5aV1bjqh_Q23odCf/static/superman/js/lib/jquery-1.10.2_d88366fd.js').done(function(){
    alert(1);
    resolve('resolve 被执行');
  }).fail(function(){
    reject('reject 被执行');
  });
})

var p1 = new Promise((resolve, reject)=>{
  $.getScript('https://ss0.bdstatic.com/5aV1bjqh_Q23odCf/static/superman/js/min_super_af0391fe.js').done(function(){
    resolve('aaaa');
  }).fail(function(e){
    reject(e)
  })
});
Promise.all([p,p1]).then(function(msg){
  console.log(msg); //["resolve 被执行", "aaaa"]
})

var p = new Promise(function(resolve){
  setTimeout(()=>{
    console.log(1)
    resolve('aaaaaaa');
  }, 3000);
});

var p1 = new Promise((resolve)=>{
  setTimeout(()=>{
    console.log(2)
    resolve('bbbbb');
  }, 1000);
});


Promise.all([p,p1]).then((msg)=>{
  console.log(msg)
});

//2
//1
//["aaaaaaa", "bbbbb"]

 

function timeout (ms) {
  return new Promise((resolve, reject) => {
    setTimeout(resolve, ms, 'done');
  })
}

timeout(2000).then((value) => {
  console.log(value);
})

const promise = new Promise((resolve, reject)=>{
  console.log('Promise');
  resolve(111);
})

promise.then((value)=> {
  console.log('resolve', value)
})

console.log('Hi')

function loadImageAsync (url) {
  return new Promise((resolve, reject) => {
    const img = new Image();
    img.onload = () => {
      resolve(img);
    }
    img.onerror = () => {
      reject(new Error('Could not load image at ' + url))
    }
    
    img.src = url;
  })
}

loadImageAsync('http://img.ivsky.com/img/fbizhi/co/201709/01/tanghongde_liange-004.jpg').then((img) => {
  console.log(img)
})

function getJSON (url) {
  return new Promise((resolve, reject)=> {
    const xhr = new XMLHttpRequest();
    xhr.open('GET', url);
    xhr.onreadystatechange = handler;
    xhr.responseType = 'json';
    xhr.setRequestHeader('Accept', 'application/json');
    xhr.send();
    
    function handler () {
      if (this.readyState !== 4) {
        return;
      }
      if (this.status == 200) {
        resolve(this.response);
      } else {
        reject(new Error(this.statusText))
      }
    }
  })
}

getJSON('./js/test.json').then((res) => {
  console.log(res)
}, (err) =>{
  console.error('出错咯', err)
})

const p1 = new Promise((resolve, reject) => {
  setTimeout(()=> {
    console.log('p1')
    reject(new Error('reject'))
  }, 3000)
})

const p2 = new Promise((resolve, reject) => {
  setTimeout(() =>{
    console.log('p2')
    resolve(p1)
  }, 1000);
})

p2.then((result) => {
  console.log(result)
}).catch(error => console.log(error))

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