SOURCE

new Promise(function (resolve, reject) { });

//
var success = true;
var myPromise = new Promise(function (resolve, reject) {
    if (success) {
        resolve("异步操作成功了");
    } else {
        reject("有意外错误了");
    }
});
console.log(myPromise);


//
var myPromise = Promise.reject("");
myPromise.then(function(vaule){
    console.log("执行",value);
});


var promise = new Promise(function (resolve, reject) {
    var a = 1
    if (a === 1) {
        resolve(a)
    } else {
        reject(error)
    }
});
promise.then(function (value) {
    console.log(value++)
    return value
}).catch(function (error) {
    console.log(error)
}).then(function (value) {
    console.log(value++)
})

// 输出：
// 1
// 2

let mylog = (msg)=>console.log(msg);
mylog("日志1");

var p = new Promise(function (resolve, reject) {
    mylog("日志2");
 });
 p.then(mylog("日志3"));
 

 //Promise.all
 console.log("Begin Promise.all 演示");
 Promise.all([
     new Promise(function(resolve){
         setTimeout(function(){
             resolve(100);
         },100);
     }),
     new Promise(function(resolve){
         setTimeout(function(){
             resolve(200);
         },200);
     }),
     new Promise(function(resolve){
         setTimeout(function(){
             resolve(300);
         },300);
     })
 ]).then(function(value){
     console.log(value);  //[100,200,300]
 });
  console.log("End Promise.all 演示");

  //Promise.race
 console.log("Begin Promise.race 演示");
 Promise.race([
     new Promise(function(resolve){
         setTimeout(function(){
             resolve(100);
         },100);
     }),
     new Promise(function(resolve){
         setTimeout(function(){
             resolve(200);
         },200);
     }),
     new Promise(function(resolve){
         setTimeout(function(){
             resolve(300);
         },300);
     })
 ]).then(function(value){
     console.log(value);  //100
 });
  console.log("End Promise.race 演示");