JavaScript

By default Jest runs tests in parallel with a “a worker pool of child processes that run tests” (Jest CLI docs). As per the Jest documentation, running tests in sequence (serially), can be helpful for debugging purposes and for test run performance reasons. ...

How does one identify whether a JavaScript file is being run directly (node file.js) or it’s being import/require-d (require('./file') in another JS file). In Python the pattern leverages the __main__ property in modules like so: if __name__ == '__main__': # do some ...

With ES6, more developers should be leveraging built-ins than are using lodash functions. Here is an ES6 implementation of lodash/underscore’s uniq: const dedupe = list => [...new Set(list)]; This post goes through the how and why this works. It explores Sets, iterabl ...

Add diagrams to your JAMStack (Jekyll/Hugo/Gatsby) blog with Mermaid JS The following post will go through how to integrate Mermaid JS, a “simple markdown-like language for generating charts”. It will initially go through the benefits of MermaidJS, followed by a gen ...

How to use Yarn Workspaces to manage applications/coding examples. Lerna isn’t required when you don’t need the git diffing and versioning facilites. What’s more Yarn Workspaces are a great lightweight tool to get up and running faster for simple Node.js monor ...

Hugo “The world’s fastest framework for building websites” is a great option for JAMStack (JavaScript, APIs, prebuild Markup) sites. Lunr.js is “A bit like Solr, but much smaller and not as bright”, it’s a pure JavaScript implementation of a Solr-lik ...

JavaScript (JS) is a lightweight, interpreted, or just-in-time compiled programming language with first-class functions. MDN Web Docs - JavaScript Detailed in this post are common JavaScript data type checks, pitfalls and idiomatic workarounds. ...

In computer science, test coverage is a measure used to describe the degree to which the source code of a program is executed when a particular test suite runs. Code coverage - Wikipedia Code coverage is usually used as a quality metric for software eg. “Our code has to have 80 ...

An example Netlify Lambda to fetch all “newsletter” posts from Pocket. Pocket is an application and web service for managing a reading list of articles from the Internet. It’s quite widely used and tightly integrated into the Firefox browser. I find that I use it extensiv ...

There are situations where new Date() or Date.now is used in application code. That code needs to be tested, and it’s always a struggle to remember how to mock/stub or spy on Date.now/new Date with Jest. This post goes through multiple approaches to mocking, stubbing and spying o ...