Learning Node.js Development

Error handling in promises

Now there's a chance that things didn't go well. We have to handle errors inside our Node applications. In that case, we wouldn't call resolve, we would call reject. Let's comment out the resolve line, and create a second one, where we call reject. We'll call reject much the same way we called resolve. We have to pass in one argument, and in this case, a simple error message like Unable to fulfill promise will do:

var somePromise = new Promise((resolve, reject) => {  setTimeout(() => {    // resolve('Hey. It worked!');    reject('Unable to fulfill promise');  }, 2500);});

Now when we call reject, we're telling the promise that it has been rejected. This means that the thing we tried to do did not go well. Currently, we ...