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Differences Between Promises and Async/Await in JavaScript
Mar 3, 2022
Introduction
JavaScript is a versatile programming language that allows developers to create dynamic and interactive web pages. Promises and Async/Await are two important features in JavaScript that are used to handle asynchronous tasks and improve the performance of web applications. In this blog post, we will discuss the differences between Promises and Async/Await in JavaScript.
Promises
Promises are a way of handling asynchronous tasks in JavaScript. They were introduced in ES6 and provide a cleaner way of handling asynchronous code than callbacks. Promises are objects that represent the eventual completion or failure of an asynchronous operation and allow us to chain multiple asynchronous operations together. Promises have three states: Pending, Fulfilled, and Rejected. A Promised is created using the
new Promise()
constructor.Async/Await
Async/Await is a new syntax for handling asynchronous tasks in JavaScript. It was introduced in ES8 and is built on top of Promises. Async/Await makes asynchronous code more readable and easier to understand by using keywords such as
async
and await
. The async
keyword is used to declare an asynchronous function, and the await
keyword is used to wait for a Promise to resolve. Async functions always return a Promise.Differences Between Promises and Async/Await
One of the main differences between Promises and Async/Await is that Promises are more low-level, while Async/Await is a higher-level abstraction. Promises are more flexible and can be used for more complex scenarios, such as chaining multiple asynchronous operations together. Async/Await is more concise and easier to read, which makes it a better choice for simpler scenarios.
Another difference between Promises and Async/Await is error handling. Promises use the
.then()
method to handle success and the .catch()
method to handle errors. Async/Await uses a try/catch
block to handle errors, which makes error handling more intuitive and less error-prone.Finally, Promises are more widely supported across different browsers and platforms, while Async/Await is a newer feature that may not be supported in older browsers. It is important to check browser compatibility before using Async/Await in your JavaScript code.
Conclusion
Promises and Async/Await are two important features in JavaScript that are used to handle asynchronous tasks. Promises are more low-level and flexible, while Async/Await is a higher-level abstraction that is more concise and easier to read. Both features have their own advantages and disadvantages, and the choice between them depends on the specific requirements of your project. It is important to understand the differences between Promises and Async/Await in order to make an informed decision.