How to escape async/await hell

async/await freed us from callback hell, but people have started abusing it — leading to the birth of async/await hell.

In this article, I will try to explain what async/await hell is, and I’ll also share some tips to escape it.

What is async/await hell

While working with Asynchronous JavaScript, people often write multiple statements one after the other and slap an await before a function call. This causes performance issues, as many times one statement doesn’t depend on the previous one — but you still have to wait for the previous one to complete.

https://medium.freecodecamp.org/avoiding-the-async-await-hell-c77a0fb71c4c

Advertisements

Write Your Own Node.js Promise Library from Scratch

Promises are the preferred async primitive in JavaScript. Callbacks are becoming increasingly uncommon, especially now that async/await is available in Node.js. Async/await is based on promises, so you need to understand promises to master async/await. In this article, I’ll walk you through writing your own promise library and demonstrate using it with async/await.

http://thecodebarbarian.com/write-your-own-node-js-promise-library-from-scratch.html

An easy guide to object rest/spread properties in JavaScript

Merging multiple JavaScript objects is a frequent task. Unfortunately JavaScript is sloppy at providing a convenient syntax to do the merge. At least until now.

In ES5 your solution is _.extend(target, [sources]) from Lodash (or any alternative), and ES2015 introduces Object.assign(target, [sources]).

Luckily object spread syntax (an ECMASript proposal at stage 3) is a step forward how to manipulate objects, providing a short and easy to follow syntax.

https://dmitripavlutin.com/object-rest-spread-properties-javascript/

AWS Lambda Node.js 8 support: what it changes for serverless developers

Node.js 8.10 runtime now available in AWS Lambda

The Lambda programming model for Node.js 8.10 now supports defining a function handler using the async/await pattern.

Asynchronous or non-blocking calls are an inherent and important part of applications, as user and human interfaces are asynchronous by nature. If you decide to have a coffee with a friend, you usually order the coffee then start or continue a conversation with your friend while the coffee is getting ready. You don’t wait for the coffee to be ready before you start talking. These activities are asynchronous, because you can start one and then move to the next without waiting for completion. Otherwise, you’d delay (or block) the start of the next activity.

Asynchronous calls used to be handled in Node.js using callbacks. That presented problems when they were nested within other callbacks in multiple levels, making the code difficult to maintain and understand.

Promises were implemented to try to solve issues caused by “callback hell.” They allow asynchronous operations to call their own methods and handle what happens when a call is successful or when it fails. As your requirements become more complicated, even promises become harder to work with and may still end up complicating your code.

Async/await is the new way of handling asynchronous operations in Node.js, and makes for simpler, easier, and cleaner code for non-blocking calls. It still uses promises but a callback is returned directly from the asynchronous function, just as if it were a synchronous blocking function.

https://aws.amazon.com/pt/blogs/compute/node-js-8-10-runtime-now-available-in-aws-lambda/


Node 8 support for AWS Lambda is here!

If you’re a serverless developer on Lambda, read on for what you need to know about Node 8. Namely: speed, Async/Await, object rest and spread, and NPX.

https://serverless.com/blog/aws-lambda-node-8-support-what-changes-serverless-developers/

11 Javascript Machine Learning Libraries To Use In Your App

iOrca whales trained through neural networks, that’s the future.

“ Wait, what?? That’s a horrible idea! “

Were the exact words of our leading NLP researcher when I first talked to her about this concept. Maybe she’s right, but it’s also definitely a very interesting concept which is getting more attention in the Javascript community lately.

During the past year our team is building Bit which makes it simpler to build software using components. As part of our work, we develop ML and NLP algorithms to better understand how code is written, organized and used.

While naturally most of this work is done in languages like python, Bit lives in the Javascript ecosystem with its great front and back ends communities…

https://blog.bitsrc.io/11-javascript-machine-learning-libraries-to-use-in-your-app-c49772cca46c

Introducing TensorFlow.js: Machine Learning in Javascript

We’re excited to introduce TensorFlow.js, an open-source library you can use to define, train, and run machine learning models entirely in the browser, using Javascript and a high-level layers API. If you’re a Javascript developer who’s new to ML, TensorFlow.js is a great way to begin learning. Or, if you’re a ML developer who’s new to Javascript, read on to learn more about new opportunities for in-browser ML. In this post, we’ll give you a quick overview of TensorFlow.js, and getting started resources you can use to try it out.

https://medium.com/tensorflow/introducing-tensorflow-js-machine-learning-in-javascript-bf3eab376db