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

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

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/