Promises

Promises are an innovative approach to managing asynchronous code in JavaScript. They provide a structured way to handle events and make your code more readable. In this blog post, we will explore the concept of Promises and Deferreds in JavaScript, using examples with jQuery and Ember.js. What are Promises? A Promise is an object that represents an event and its lifecycle. It starts in a pending state when it is called and transitions to a resolved or rejected state when the event is completed....

Error handling is a crucial aspect of any Node.js application development. Failing to handle errors properly can lead to crashes, bugs, and security vulnerabilities. In this blog post, we will explore various techniques and best practices for effective error handling in Node.js. Creating Exceptions In Node.js, errors are handled through exceptions. To throw an exception, you can use the throw keyword followed by a value. In client-side code, the value can be any JavaScript value, such as a string, number, or object....

Learn how to retrieve the result of an asynchronous function, whether it is promise-based or callback-based, using JavaScript. Imagine you encounter this scenario: you need to return the result of an asynchronous call from the original function. Here is a simplified example: const mainFunction = () => { const result = asynchronousFunction(); return result; } However, asynchronousFunction() performs an asynchronous operation, such as a fetch() call, and cannot directly return the result value....

In the world of Node.js, many APIs and libraries were built before the introduction of promises. As a result, they rely on a callback-based solution. However, working with nested callbacks can lead to a complex and messy code structure commonly known as “callback hell.” Thankfully, there is a solution: the use of promises and the await keyword. To remove callbacks and make use of promises, Node.js provides a useful utility called promisify from the util module....

Promises are a powerful tool for dealing with asynchronous code in JavaScript, allowing you to avoid the callback hell. In this blog post, we will explore how to use promises, including creating promises, consuming promises, chaining promises, handling errors, and orchestrating promises. Introduction to Promises A promise is a proxy for a value that will eventually become available. It provides a way to work with asynchronous code without writing too many callbacks....

Node.js built-in modules are well-known for not being promise-based. This was because these modules were created before promises became popular. Although the promisify function has been available for some time, Node.js introduced a new promise-based API starting from version 10. Currently, this new API is only available for the fs built-in module, and it remains uncertain whether it will be implemented for other native modules in the future. To utilize this new API, follow these steps:...

In JavaScript, there are situations where we need to wait for multiple promises to resolve before continuing the execution of our code. Instead of waiting for one promise to resolve and then starting the next one, it would be more efficient to start all the promises simultaneously and wait for all of them to finish. In this blog post, we will discuss how to achieve this using the await keyword and the Promise....

In this blog post, we will explore how to effectively work with promises in Svelte templates and leverage their power in managing asynchronous events in JavaScript. Promises have become a valuable tool in handling asynchronous operations, and with the introduction of the await syntax in ES2017, working with promises has become even easier. Svelte provides the {#await} syntax in templates, which allows us to directly incorporate promises at the template level....

The Fetch API is a modern approach to making asynchronous network requests in the browser. It offers a more streamlined and intuitive way to handle AJAX calls compared to the older XMLHttpRequest (XHR) approach. In this article, we will explore the basics of using the Fetch API and the features it provides. Introduction to the Fetch API Introduced as a standardized replacement for XHR, the Fetch API uses Promises as a building block for asynchronous network requests....

The Event Loop is a fundamental concept to understand in Node.js. It explains how Node can be asynchronous and have non-blocking I/O, which is what makes it so successful. Node.js code runs on a single thread, meaning that only one thing can happen at a time. While this may seem like a limitation, it simplifies programming by eliminating the need to worry about concurrency issues. However, it is important to be mindful of how you write your code to avoid blocking the thread....