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Async Await Javascript Example: Javascript Explained

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Async Await is a new feature added to JavaScript ES7 with the aim of making asynchronous programming easier and faster. Asynchronous programming describes tasks that are completed non-linearly and out of order. Asynchronous code can make applications function faster and can improve code readability. This article will explain the basics of Async Await as well as the benefits and how it can improve performance.

Basics of Asynchronous JavaScript

Non-linear programming has been around for a while in JavaScript. Prior to the ES6 version of the language, developers used callbacks and promises to write asynchronous code. With the introduction of ES7, Async Await was added which allows the writing of code in a synchronous manner and handles the asynchronous components of that code behind the scenes.

Async Await is a combination of two JavaScript keywords, async and await. The async keyword tells the browser that a function is asynchronous. When the await keyword is used, it tells the browser that it must wait until an asynchronous operation has finished before continuing. The result of the asynchronous operation must be stored in a variable that is used with the await keyword.

Async Await is a great way to simplify asynchronous code and make it easier to read and understand. It also helps to reduce the amount of code that needs to be written, as the asynchronous components are handled automatically. Async Await is becoming increasingly popular and is now supported by all major browsers.

Benefits of Using Async Await

The benefit of using Async Await is that it makes writing asynchronous code easier. The code is easier to read, because it appears to be synchronous code and can be written as a single block of code, instead of having multiple lines of callback functions. It also simplifies error handling, because errors can be handled using traditional try-catch blocks instead of having to handle and propagate errors through callbacks.

Async Await also lends itself to simpler debugging, because the stack trace is easy to read. Additionally, it’s easy to keep track of where the code is in its execution, because you don’t have to think about when callbacks will fire or what value will be passed. Finally, Async Await can improve performance because it allows for more efficient use of time by letting asynchronous operations run in parallel, so that you don’t have to wait for each function to finish before continuing.

Another benefit of using Async Await is that it allows for better code organization. By using Async Await, you can break up your code into smaller, more manageable chunks, which makes it easier to debug and maintain. Additionally, it can help reduce the amount of code you need to write, since you don’t have to write multiple lines of callback functions.

Writing an Async Await Function

An async function is denoted by using the keyword async before the function keyword. This signals to the browser that this is an asynchronous function. Your return value within an async function must be either a promise or a value. A promise is returned when an asynchronous operation needs to occur, while a value is returned when a synchronous task has finished.

An await keyword is used within an async function to pause execution and wait for an asynchronous operation to complete. The await keyword must be preceded by the keyword async. The keyword await can only be used inside an async function. This means that if you are writing code inside a regular function, you must wrap it in an async function.

When using the await keyword, it is important to remember that the code will not continue to execute until the asynchronous operation has completed. This means that if you are waiting for a response from an API, your code will not continue until the response has been received. This can be beneficial in some cases, as it allows you to ensure that all of the necessary data has been received before continuing with the code.

Error Handling with Async Await

Error handling with async await is the same as it is with any other form of error handling in JavaScript. You wrap your async function in a try-catch block, and any errors thrown will be caught by the catch part of the block. Any errors that are thrown within an async function will also cause any subsequent functions that depend on the result of this async operation to throw an error.

It is important to note that errors thrown within an async function will not be caught by the try-catch block, and must be handled separately. Additionally, errors thrown within an async function can be handled by using the .catch() method, which allows you to specify a callback function to be executed when an error is thrown.

How Async Await Improves Performance

One way that Async Await improves performance is by making it easier to write code that takes advantage of web workers. Web workers are JavaScript threads that run tasks in the background while the main thread continues with its task. By using Async Await, it’s easy to let a web worker perform tasks in the background while your main thread does other tasks in the meantime.

Another way that Async Await improves performance is by allowing for more efficient use of time. By using Async Await, you can start multiple asynchronous operations in parallel and handle them all without having to wait for each operation to finish before continuing with the next one.

Async Await also helps to reduce the amount of code that needs to be written. By using Async Await, you can write code that is more concise and easier to read. This makes it easier to debug and maintain your code, which can lead to improved performance.

Working with Promises and Async Await Together

Async Await can work with promises in cases where an asynchronous operation needs to start before the await keyword is used. For example, if you need to fetch data from somewhere before using it, you can wrap your fetch call in a promise and then wait for it to resolve before awaiting it. Alternatively, you can directly use promises inside an async function by wrapping them in an await statement.

It is important to note that when using promises and async await together, the promise must be resolved before the await keyword is used. If the promise is not resolved, the await keyword will not work and the code will not execute as expected. Additionally, it is important to ensure that the promise is properly handled and any errors are caught and handled appropriately.

Conclusion

Async Await is a powerful addition to JavaScript ES7 that makes writing asynchronous code much simpler and easier than before. By combining the async and await keywords, developers can write code that appears synchronous but all the underlying asynchronous operations are handled for you. Additionally, Async Await makes error handling simpler by allowing try-catch blocks to be used, and improves performance by allowing operations to run in parallel.

Async Await is a great tool for developers who need to write asynchronous code, as it simplifies the process and makes it easier to read and understand. It also allows for better performance, as operations can be run in parallel, and makes error handling simpler. Async Await is a great addition to JavaScript ES7 and is sure to be a popular tool for developers.

Sarang Sharma

Sarang Sharma

Sarang Sharma is Software Engineer at Bito with a robust background in distributed systems, chatbots, large language models (LLMs), and SaaS technologies. With over six years of experience, Sarang has demonstrated expertise as a lead software engineer and backend engineer, primarily focusing on software infrastructure and design. Before joining Bito, he significantly contributed to Engati, where he played a pivotal role in enhancing and developing advanced software solutions. His career began with foundational experiences as an intern, including a notable project at the Indian Institute of Technology, Delhi, to develop an assistive website for the visually challenged.

Written by developers for developers

This article was handcrafted with by the Bito team.

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