then( fact => console.log(fact) // actually outputs a string ).catch( error => console. You’d have to nest these calls inside each other: request.get(url, function(error, response, mongoUrl) getChuckNorrisFact(url). But what if both calls depend on each other? What if the data you’re fetching is the MongoDB URL that you need to connect to? They are functions that are usually passed on as a second parameter to another function that is fetching data or doing an I/O operation that takes time to complete.įor example, try making an API call using the request module or connecting to a MongoDB database. Callback HellĬallbacks are a useful feature of JavaScript’s that enables it make asynchronous calls. For a more vivid explanation, you can check out this article which explains them thoroughly. I am not going to delve too deeply into the details of callback and its pros and cons or alternatives like promises and async/await. 69,599 developers are working on 7,633 open source repos using CodeTriage.
As a developer who is fairly new and getting acquainted with those challenges, I have never run into a challenge or inconvenience more frequently - or more memorable - than with callback functions. The easiest way to get started contributing to Open Source javascript projects like freecodecamp Pick your favorite repos to receive a different open issue in your inbox every day. Back-end developers run into challenges all the time while building applications or testing code.
0 kommentar(er)
