Webolution Designs

Creating a Promise

Share This Post

Promises are used for asynchronous code. It is a temporary holder for a value that gets returned by an asynchronous call. For example, a call to a web service might use a promise. You can call the web service with a promise and once it is fulfilled, you can run some code. Here is the syntax…

let myPromise = new Promise(
    function(resolve, reject){
        setTimeout(resolve, 1000, ‘a value’);
    }
);
console.log(myPromise); 

Here we are creating a promise. Within the promise method, we have an anonymous function that is making the promise call. In here is where you might find a call to a web service. In our example, we are simply running a setTimeout function to simulate a call to a service that might take a second. Notice the two parameters in the function…resolve and reject. Those are the two things that can happen to a promise. It can be rejected. We can then handle the rejection, or it can be resolved (fulfilled). This settles the promise and we can programmatically handle the response.

In our code, you should see the promise logged to the console. It is in a pending state because we haven’t settled it. We haven’t done anything with it yet. Feel free to change the resolve to reject in the setTimeout to see the difference.

Happy Coding!

Clay Hess

Subscribe To Our Newsletter

Get updates and learn from the best

More To Explore

Code

Curriculum Innovation or Confusion

It is an early Monday morning just prior to the beginning of the semester.  A faculty member walks into the institution where he teaches.  He

Code

Creating a Promise

Promises are used for asynchronous code. It is a temporary holder for a value that gets returned by an asynchronous call. For example, a call

Do You Want To Boost Your Business?

drop us a line and keep in touch

Excuse Our Mess! We are currently remodeling!

We are currently in the process of redesigning our site. We appreciate your patience as some areas of our site show chipping and paint peeling. We hope to have it sparkling soon!

small_c_popup.png

Learn how we helped 100 top brands gain success.

Let's have a chat