Async/await makes it easy to integrate asynchronous behavior with imperative constructs like for loops, if statements, and try/catch blocks. Unfortunately, it doesn't do the same for functional constructs like forEach, map, reduce, and filter. Using these constructs with async functions leads to behavior that can seem downright baffling. In this article, I'll show you some common gotchas for async functions with JavaScript's built-in functional array methods and how to work around them.

Firebase is a great tool for getting data from a server to a client. Firebase handles caching, retries, socket management, and all the other unpleasant details of getting data to a client with spotty internet connection. In particular, Firebase is excellent for mobile web and mobile apps. In this article, I'll walk you through using Firebase with Preact, a lightweight React alternative, to build a simple app with server-side rendering.

Node.js 6.6.0 added a sporadically useful bug/feature: logging unhandled promise rejections to the console by default. In other words, the below script will print an error to the console:

By virtue of the event loop, scheduling tasks in Node.js is relatively straightforward. Plain old setTimeout() and setInterval() are sufficient for many basic use cases where you would normally use cron. However, things get more interesting when you need durable transactional scheduling, for use cases like:

I find the existence of tools like nvm baffling. I could understand if setting up Node.js required an actual installer or compiler or python, but node has pre-built binaries for most operating systems. Node and npm are both portable standalone executables, so all you need is the right binary for your OS in the right place on your file system. Especially if you're switching back and forth between Node 6.x and 7.6.0 for async/await, you should simplify your node version management workflow rather than using yet another bloated tool.

Async/await in Node.js opens up a host of powerful design patterns. Tasks that used to take complex libraries or intricate promise chaining can now be done with rudimentary if statements and for loops. I already wrote about these kind of design patterns with co, but async/await makes these patterns accessible in vanilla Node.js, no outside libraries required.

Arguably the biggest new feature in Node.js 7.6.0 is that the much awaited async function keyword is now available without a flag. Callback hell and promise hell are now in the past. But, like Uncle Ben always reminded us, with great power comes great responsibility, and async/await gives you a lot of new and exciting ways to shoot yourself in the foot. You still need to handle errors and be aware of the async nature of your code, otherwise you'll inevitably be complaining about "async/await hell" in 6 months.

WebAssembly is an exciting new language that many JavaScript engines have added support for. WebAssembly promises to make it much easier to compile languages like C and C++ to something that runs in the browser. However, I'm most excited about the ability to write optimized custom arithmetic and buffer manipulations, like, say, fast decimal floating point arithmetic in JavaScript without having to wait for TC39 to get around to it. In this article, I'll show you how to get a couple rudimentary WebAssembly examples running in Node.js, and run a couple trivial benchmarks to show the performance impact.