let myFirstPromise = new Promise((resolve, reject) => {
// We call resolve(...) when what we were doing asynchronously was successful, and reject(...) when it failed.
// In this example, we use setTimeout(...) to simulate async code.
// In reality, you will probably be using something like XHR or an HTML5 API.
setTimeout(function(){
resolve("Success!"); // Yay! Everything went well!
}, 250);
});
myFirstPromise.then((successMessage) => {
// successMessage is whatever we passed in the resolve(...) function above.
// It doesn't have to be a string, but if it is only a succeed message, it probably will be.
console.log("Yay! " + successMessage);
});
(https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Promise)