Converting a string to a number in JavaScript is surprisingly subtle. With NaN, implicit radixes, and numbers vs Numbers, there are a lot of ways to shoot yourself in the foot. In this article, I'll cover the tradeoffs of parseFloat() vs Number() and Number.isNaN() vs isNaN(). I'll also describe how to enforce these rules with eslint.

Mongoose 5.4 was released on December 14, with 13 new features. The overarching theme for 5.4 is making Mongoose SchemaTypes more configurable, but that isn't the whole story. Mongoose 5.4 has several new features that will help you make your apps more robust and concise. In this article, I'll cover the new Model.events property and the new count option for virtual populate.

The V8 team announced that they were making some major performance improvements to async/await, including adding a --async-stack-traces option that will make debugging async functions easier. You can try out these new options with a nightly Node.js build. For example, here's the command I ran to download the January 8, 2019 nightly build of Node.js 12:

Mongoose 5.4 was released on December 14, with 13 new features. The overarching theme for the most important new features is making Mongoose SchemaTypes configurable at the level of individual types. Before digging in to the new features, let's first review what a SchemaType is.

In August, the Semmle Security Research Team found a security vulnerability affecting all versions of Mongoose before 5.2.12 and 4.13.17. We released a fix on August 30 and encouraged everyone to upgrade via Twitter, our Slack channel, and our Gitter chat. HackerOne recently released a formal disclosure of this issue on November 30. This blog post constitutes Mongoose's full disclosure after a period of responsible disclosure. In this article, I'll describe the vulnerability and how Mongoose patched it.

This post is very different from my usual JavaScript beat. I recently turned 30, so I wanted to write some reflections for myself. I wasn't going to publish this post at first, I'm usually not the kind of person who shares this much in a public forum. But then I thought it would be fun to put this out there and see what people who stumble across it think. Maybe someone out there will find this sort of straight-from-the-heart advice helpful. I benefitted from similar advice, perhaps you will to. Without further ado:

Stripe's v3 API introduced a controversial change: you can no longer use Stripe with custom payment forms, you must use the new Stripe Elements interface. This change is brutal from a developer experience perspective, because you need to figure out how to rewrite your app to use the new API, and the existing docs are written for vanilla JavaScript. There is a React library, but it is heavy and there's no information as to whether it actually works with Preact. In this article, I'll present a basic proof of concept of using the vanilla Stripe Elements library and Preact.

Since ES6, JavaScript enjoys support for classes and static functions akin to static functions in other object-oriented languages. Unfortunately, JavaScript lacks support for static properties, and recommended solutions on Google fail to take into account inheritance. I ran into this problem when implementing a new Mongoose feature that requires a more robust notion of static properties. Specifically, I need static properties that support inheritance via setting prototype or via extends. In this article, I'll describe a pattern for implementing static properties in ES6.