May 20Sharing React Query across micro frontends with single-spa and webpack module federationIn this article, I will show how to setup multiple micro frontends using single-spa and module federation. Each micro frontend will be using React Query to fetch and cache data. I will then demonstrate how multiple micro frontends can use the same QueryClient to share cached data. The purpose is…Single Spa8 min read
Oct 5, 2020Authoring a JavaScript library that works everywhere using RollupIn this article, we aim to create and publish a library that can be used, without any changes in the code, in both client side and server side applications. We need to fulfill the following use cases: The library is written in ES6+, using import and export keywords The library…Webpack7 min read
Sep 24, 2020You don’t need React to use JSXIn this article, we explain the new JSX Transform, and how to use JSX without React. — The official React blog does not get many updates, so a new post is always attention worthy, but this week’s post, Introducing the New JSX Transform, could be a much bigger deal than it seemingly appears. In this post, Luna Ruan announces a new JSX Transform, and one of the…Babel6 min read
Aug 14, 2020Beware of “Algorithm Interview” articlesI received an email digest from a popular blogging platform which included after the first few serious and news worthy links some more click-baity content. The article that caught my eye is titled something along the lines of “Questions and Answers to Algorithm Interviews”. In my experience, with few exceptions…Java Script5 min read
Feb 15, 2020Using environment variables in a React applicationIn this article we’ll see how to use environment variables in a React application. Specifically, we’ll look at two kinds of environments variables: Build time variables: these are variables that are provided when the application is compiled (typically when npm run build is executed). …6 min read
Feb 8, 2020Adding GraphQL to a RESTful APIJune 2021 update: while some of the content of this article remains accurate (and hopefully useful), it is a bit of a contrived example. It assumes that there is an existing REST api running on Express that needs to be maintained, while also exposing a GraphQL endpoint. In reality, a…Graph QL11 min read
Jan 27, 2020Adding a Redis cache to an Express appRedis is, according to its own website, “an open source (BSD licensed), in-memory data structure store, used as a database, cache and message broker”. In other words, Redis can be used as a blazing fast cache, and it’s dead simple to use. Let’s use as an example a simple Express…Express3 min read
Jan 22, 2020Ternaries make code difficult to read and maintain.Clean code is code that is easy to understand, easy to review and easy to change. Ternaries, especially as one line functions, are rarely any of these things. Let’s write a function that returns whether an integer is positive or negative. This can be simply and quickly written as is: …2 min read
Sep 21, 2019Simplify Redux reducers with immerBefore getting too deep in the weeds, we need to understand what immutability is. It all has to do with reference and value equality. Reference equality: we compare references (pointers), and if the two instances are the same, then obj1 === obj2 Value equality: we compare values, and if the…Redux4 min read
Published in The Startup·Sep 13, 2019Working with currency in JavaScriptWorking with currencies in JavaScript can be more complicated than it seems. The first issue we have is that a monetary amount is usually represented using a float, so multiplying and dividing them can be tricky. Just try typing 10 / 3 or 3.33 * 3 in a JavaScript console. …Java Script3 min read
