JavaScript Promise

javascript Promise
Promise is a Javascript object for asynchronous operation
1.state 
2.producer  vs consumer 

 

Producer 
//불필요한 네트워크 받을 수있다  (executor 함수가 자동적으로 실행이 되기때문이다) 
// the executor runs automatically
const promise = new Promise((resolve, reject) => {
//heavy work
);

 

Consumer(then, catch, finally)

promise.then(value => {

});