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Why JavaScript Promises are awesome

Methmi on August 26, 2022

What is a Promise? A promise, in computer science, is basically a concept that handles a value that is to be produced in the future, aft...

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Sokhavuth TIN • Aug 26 '22 • Edited

To highlight JavaScript syntax, you just write the word JavaScript or js after the opening triple quote:

let myPromise = getPromise(URL_RETURNING_MULTIPLE_ITEMS);
promise.then(result => {
   // extracts URL of oneItem
   let oneItem = JSON.parse(result).results[0].url;
   return oneItem; // returns the URL
}).then(oneItemURL => {
   console.log(oneItemURL);
   return getPromise(oneItemURL); // new promise returned
}).then(itemData => {
   console.log(JSON.parse(itemData));
}).catch(error => {
   console.log(‘Error caught. In the Catch block’, error);
});

Methmi • Aug 26 '22

Thank you so much for that input!

Dennis • Aug 27 '22

Great article

It really helped me think deeply about promises. A promise is basically an object that represents the result of an asynchronous operation. That result can be your desired value or an error. For example if you are making a fetch request for some posts then the desired result is the array of posts. If something goes wrong on the server then the result is an error telling you what went wrong. Either way you get a result from the promise, a desired value or an error.