Cleaner Code with Async / Await Tutorial | JavaScript Tutorial

Asynchronous programming in JavaScript used to be difficult to write clean code with. Today we have options. You can write asynchronous code with callbacks (and face the scary rightward slant of callback hell), use Promises, or use async / await. I’ll show you why I mostly use a combination of async / await and Promises to write cleaner asynchronous code.

I mentioned that we have options when writing asynchronous code in JavaScript. For a good explaination on the history of Asynchronous JavaScript and the 3 approaches (callbacks, Promises, async/await) to writing async code

I wanted to extend that article by speaking a little bit more about how you can use a combination of async / await, Promises, and async’s ability to return a Promise to keep your async code as clean as possible.

Writing Async Code (with Promises)

Let’s say you have a traditional JavaScript function that maneuvers asynchronicity through utilizing a callback parameter. We want to make this asynchronous using async / await.

// ===========================================================
// == This is the function that we want to make asynchronous
// == with async / await.
// ===========================================================

function getJobApplications (callback) {
  database.getJobApplications((err, data) => {
    callback(err, data)
  })
}

In this example, the database function getJobApplications expects a callback, so there’s nothing we can do about that, per say. But, we can make it async by Promisifying it.

// ============================================================
// == In order to make this function asynchronous, we "promisify" it.
// == We inner-wrap it with a Promise so that the calling function can 
// == wait for it to be resolved or rejected.
// ============================================================

function getJobApplications () {
  return new Promise((resolve, reject) => {
    database.getJobApplications((err, data) => {
      if (err) return reject(err);
      resolve(data);
    })
  })
}

This approach of Promisfying your function is pretty common. We wrap the inside of the function with a promise and manually specify when the function should resolve() (as the result of a success state) or reject() as the result of encountering an error.

This is good… and it works, but it’s not very DRY (do not repeat yourself). You can quickly end up writing several return new Promise((resolve,reject) => {}) inner-wrappers for just about everything you’d like to make async.

Anytime you have a function that relies on a callback that you want to wait on with await, you’ll pretty much always have to Promisify the function.

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Cleaner Code with Async / Await Tutorial | JavaScript Tutorial
Samanta  Moore

Samanta Moore

1621137960

Guidelines for Java Code Reviews

Get a jump-start on your next code review session with this list.

Having another pair of eyes scan your code is always useful and helps you spot mistakes before you break production. You need not be an expert to review someone’s code. Some experience with the programming language and a review checklist should help you get started. We’ve put together a list of things you should keep in mind when you’re reviewing Java code. Read on!

1. Follow Java Code Conventions

2. Replace Imperative Code With Lambdas and Streams

3. Beware of the NullPointerException

4. Directly Assigning References From Client Code to a Field

5. Handle Exceptions With Care

#java #code quality #java tutorial #code analysis #code reviews #code review tips #code analysis tools #java tutorial for beginners #java code review

Terry  Tremblay

Terry Tremblay

1602147513

Now Learn JavaScript Programming Language With Microsoft

icrosoft has released a new series of video tutorials on YouTube for novice programmers to get a hands-on renowned programming language — JavaScript.

This isn’t the first attempt by Microsoft to come up with video tutorials by beginner programmers. The company also has a series of YouTube tutorials on Python for beginners.

For JavaScript, Microsoft has launched a series of 51 videos as ‘Beginner’s Series to JavaScript,’ for young programmers, developers and coders who are interested in building browser applications using JavaScript. These video tutorials will also help programmers and coders to use relevant software development kits (SDKs) and JavaScript frameworks, such as Google’s Angular.


“Learning a new framework or development environment is made even more difficult when you don’t know the programming language,” stated on the Microsoft Developer channel on YouTube. “Fortunately, we’re here to help! We’ve created this series of videos to focus on the core concepts of JavaScript.”

It further stated — while the tutorials don’t cover every aspect of JavaScript, it indeed will help in building a foundation from which one can continue to grow. By the end of this series, Microsoft claims that the novice programmers will be able to work through tutorials, quick starts, books, and other resources, continuing to grow on their own.


#news #javascript #javascript tutorial #javascript tutorials #microsoft tutorials on javascript

Giles  Goodwin

Giles Goodwin

1603857900

4 Ways You Can Get Rid of Dirty Side Effects for Cleaner Code in JavaScript

According to an analysis, a developer creates 70 bugs per 1000 lines of code on average. As a result, he spends 75% of his time on debugging. So sad!

Bugs are born in many ways. Creating side effects is one of them.

Some people say side effects are evil, some say they’re not.

I’m in the first group. Side effects should be considered evil. And we should aim for side effects free code.

Here are 4ways you can use to achieve the goal.

1. use strict;

Just add use strict; to the beginning of your files. This special string will turn your code validation on and prevent you from using variables without declaring them first.

#functional-programming #javascript-tips #clean-code #coding #javascript-development #javascript

wp codevo

wp codevo

1608042336

JavaScript Shopping Cart - Javascript Project for Beginners

https://youtu.be/5B5Hn9VvrVs

#shopping cart javascript #hopping cart with javascript #javascript shopping cart tutorial for beginners #javascript cart project #javascript tutorial #shopping cart

Javascript : Async Await in Javascript | Javascript Interview questions.

Explained in detail about

  • Async
  • Await
  • Fetching country data using Async & Await
  • How Async & Await better than promise

Dont miss to watch the video & ask your questions or doubts in comments

https://youtu.be/pJbsd2vAqdI

#javascript #async #await