javascript Promise
new Promise(function(resolve, reject){
setTimeout(function(){
console.log("resolve", 1);
resolve("result");
}, 2000);
}).then(function(v){
return new Promise(function(resolve, reject) {
console.log("then", 2);
setTimeout(function(){
console.log("then", 3);
//resolve(v);
}, 2000);
});
}).then(function(v){
console.log("then then", 4);
console.log("then then", v);
});