Posted on Oct 18 Imagine that you’re a top singer, and fans ask day and night for your upcoming song.To get some relief, you Promise to send it to them when it’s published. You give your fans a list. They can fill in their email addresses so that when the song becomes available, all subscribed parties instantly receive it. And even if something goes very wrong, say, a fire in the studio, so that you can’t publish the song, they will still be notified.Everyone is happy: you, because the people don’t crowd you anymore, and fans, because they won’t miss the song.This is a real-life analogy for things we often have in programming.Now, just like our singer's promise to deliver that eagerly awaited song, JavaScript also offers a powerful tool to handle similar situations in programming. Enter Promises.In the realm of programming, a "Promise" is like a contract. It's an object representing the eventual outcome of an asynchronous operation. This could be something like fetching data from a server, reading a file, or any task that takes a significant amount of time.The Three States of a PromisePromises in JavaScript have three possible states:Pending: This is the initial state. The operation hasn't been completed yet.Fulfilled: The operation was successful, and the Promise now has a result.Rejected: Something went wrong, and the operation couldn't be completed. The Promise has an error.Just like our singer's promise to deliver the song, JavaScript Promises uphold their commitment, ensuring that you'll eventually get a result, even if there are unexpected hurdles along the way.Now, let's dive into the practical aspect of working with Promises in JavaScript.A Promise in JavaScript is created using the new Promise() syntax. Here's an example:In this example, we've created a Promise named myPromise. It's constructed with a callback function that takes two parameters:** resolve** and reject. These are functions provided by JavaScript to handle the eventual completion or failure of the asynchronous operation.If the operation is successful, we call** resolve** with the result. If there's an error, we call reject.Handling Promise StatesUsing .then() and .catch()To manage the outcomes of a Promise, we use the .then() *and *.catch() methods.Here, if the Promise resolves, the first function inside .then() executes. If it rejects, the function inside .catch() handles the error.Returning Values from PromisesYou can return values from a resolved Promise using return.In this example, the resolved Promise returns the value 'Returned value'.In summary, Promises are a fundamental feature in modern JavaScript development, providing an organized and efficient way to handle asynchronous tasks. They allow for smoother execution of code, ensuring that results are managed appropriately, even in the face of unexpected challenges.Subscribe to our NewsletterStay up-to-date with the latest in JavaScript development! Subscribe to our daily newsletter for insightful articles, tutorials, and news delivered straight to your inbox.SubscribleTemplates let you quickly answer FAQs or store snippets for re-use. Are you sure you want to hide this comment? It will become hidden in your post, but will still be visible via the comment's permalink. Hide child comments as well Confirm For further actions, you may consider blocking this person and/or reporting abuse Chakir QATAB - Oct 7 Sumit Bhanushali - Oct 6 Robson Antonio Lima Mendonça - Oct 10 Dsysd Dev - Oct 10 Once suspended, umahichristopher will not be able to comment or publish posts until their suspension is removed. Once unsuspended, umahichristopher will be able to comment and publish posts again. Once unpublished, all posts by umahichristopher will become hidden and only accessible to themselves. If umahichristopher is not suspended, they can still re-publish their posts from their dashboard. Note: Once unpublished, this post will become invisible to the public and only accessible to christopher. They can still re-publish the post if they are not suspended. Thanks for keeping DEV Community safe. Here is what you can do to flag umahichristopher: umahichristopher consistently posts content that violates DEV Community's code of conduct because it is harassing, offensive or spammy. Unflagging umahichristopher will restore default visibility to their posts. DEV Community — A constructive and inclusive social network for software developers. With you every step of your journey. Built on Forem — the open source software that powers DEV and other inclusive communities.Made with love and Ruby on Rails. DEV Community © 2016 - 2023. We're a place where coders share, stay up-to-date and grow their careers.