Recent Posts

• Declaring over updating RxJS observables

  Coding Jun 2, 2023 <100 views

  Declare how your RxJS observable is computed from other observables. Don't update other observables when your observable changes.

  • RxJS
  • TypeScript
  • Angular

• Best of Lodash

  Coding Jun 2, 2023 <100 views

  A collection of Lodash functions that are still useful in modern JavaScript.

  • Lodash
  • TypeScript

• Injecting an HTML snippet into every 11ty post

  Coding Jul 21, 2022 194 views

  Learn how to inject a rendered Nunjucks template into every post of your Eleventy blog.

  • Eleventy
  • JavaScript

• Rendering a file structure with Prism in Eleventy

  Coding Jun 15, 2022 <100 views

  Learn how to display a file system structure nicely on your Eleventy website with Prism.

  • Eleventy
  • JavaScript

• Why Microfrontends?

  Microfrontends Jun 10, 2022 292 views

  Learn about the reasons to adopt web-component based microfrontends. What can you gain and what are the trade-offs?

• Building an idempotent cron job with at-least-once delivery

  Node.js Jun 9, 2022 306 views

  Learn to build an idempotent at-least-once delivery of notifications in a scheduled Node.js batch job.

  • Node.js
  • TypeScript
  • Knex

• Showing Plausible view counts in an Eleventy blog

  Coding Jun 8, 2022 <100 views

  Learn how to integrate the retrieval of page view stats from the Plausible Analytics API into your Eleventy build process to show them in your blog or website.

  • Eleventy
  • Plausible

• Building an asynchronous batch job

  Node.js Jun 3, 2022 1320 views

  Learn to structure an asynchronous batch job in a Node.js application and how to isolate the functionality from the endpoint controllers.

  • Node.js
  • TypeScript
  • Knex
  • Pino

• Custom-themed Mermaid diagrams in Eleventy

  Coding Jun 3, 2022 356 views

  Learn how to use Mermaid diagrams embedded in your Markdown files in Eleventy. Globally define a custom theme that is used in each diagram.

  • Eleventy
  • JavaScript

• Node.js subcommands without CLI library

  Node.js Jun 2, 2022 275 views

  Learn to start your Node.js application with different subcommands. Implement a server mode beside commands for batch jobs in the same codebase.

  • Node.js
  • TypeScript

• Axios HTTP request authentication with JWT

  Node.js May 26, 2022 5247 views

  Learn to authenticate outgoing HTTP requests with Axios interceptors. Retrieving JWT with different scope, caching the JWT and attaching the authorization header.

  • Node.js
  • TypeScript
  • Axios
  • JWT

• Axios HTTP error handling in Express.js

  Node.js May 26, 2022 3947 views

  Don't catch all exceptions! Learn to handle erroneous HTTP responses of Axios with an Express.js handler returning a 500 and logging an error.

  • Node.js
  • TypeScript
  • Express.js
  • Axios
  • Pino

• Pino JSON logging of Axios HTTP requests

  Node.js May 25, 2022 1805 views

  Learn to configure the Pino JSON logger to automatically log each outgoing Axios HTTP request.

  • Node.js
  • TypeScript
  • Axios
  • Pino

• Connection pooling with Axios and agentkeepalive

  Node.js May 25, 2022 7317 views

  Learn to use a connection pool with Axios and agentkeepalive for HTTP requests in a TypeScript Node.js service.

  • Node.js
  • TypeScript
  • Axios

• Organizing and testing HTTP requests

  Node.js May 24, 2022 520 views

  Learn to send HTTP requests with Axios in a TypeScript Node.js service. How to mock responses in local development and tests with Jest, mockserver and supertest.

  • Node.js
  • TypeScript
  • Express.js
  • Axios
  • Jest

• Single schema multi-tenancy in Node.js with Postgres

  Node.js May 21, 2022 1118 views

  Learn to do multi-tenancy in a single Postgres schema in a TypeScript Node.js app. Avoid performance overhead while minimizing the risk of data exposure.

  • Node.js
  • TypeScript
  • Express.js
  • Knex
  • Postgres
  • JWT

• Testing Knex SQL queries with Jest and testcontainers

  Node.js May 20, 2022 3215 views

  Learn to test your Knex SQL queries with a single automatically spawned Docker Postgres database. Using testcontainers and Jest global setup and teardown.

  • Node.js
  • TypeScript
  • Knex
  • Postgres
  • Testcontainers

• Creating a Node.js DAO with Knex.js

  Node.js Apr 24, 2022 1247 views

  Learn how to build a DAO in Node.js to execute SQL queries with Knex.js. Providing CRUD operations for a REST entity persisted in the PostgreSQL database.

  • Node.js
  • TypeScript
  • Knex
  • Postgres

• Knex.js schema migrations with Postgres in Node.js

  Node.js Apr 20, 2022 3245 views

  Learn how to use Knex.js schema migrations to create a first Postgres database table. Setup scripts to allow a local database reset.

  • Node.js
  • TypeScript
  • Knex
  • Postgres

• Connecting a Node.js app with a Postgres database

  Node.js Apr 16, 2022 3277 views

  Learn how to connect a Node.js application both with a local Postgres database in docker-compose and with a production database.

  • Node.js
  • TypeScript
  • Knex
  • Postgres
  • Docker

• Resolve a list of promises synchronously

  Coding Apr 15, 2022 5261 views

  Learn how to execute and resolve a list of JavaScript promises synchronously instead of in parallel with Promise.all.

  • Node.js
  • TypeScript
  • JavaScript

• Why I dislike test-driven development

  Process Apr 4, 2022 <100 views

  About slow feedback loops in test-driven development (TDD) and its shortcomings. A plea for writing tests later.

  • TypeScript

• JWT authentication with JWKS in Express.js

  Node.js Apr 2, 2022 3360 views

  Learn how to implement JWT authentication with JWKS in a TypeScript Express.js service. How to disable auth locally and suppress tokens in production logs.

  • Node.js
  • TypeScript
  • Express.js
  • JWT
  • Pino

• Okta Breach - Don't outsource your business model

  Process Mar 25, 2022 <100 views

  With the handling of the LAPSUS$ breach, Okta has shown how to not do security and communication. Three core learnings from #OktaBreach.

• Managing configs with TypeScript code in Node.js

  Node.js Mar 21, 2022 4005 views

  Learn how to build local and production configs within TypeScript code instead of JSON or YAML files. Part 6 of the Node.js microservice architecture series.

  • Node.js
  • TypeScript

• JSON Logging with Pino in Express.js

  Node.js Mar 10, 2022 7381 views

  Learn how to add the JSON Pino logger into a TypeScript Express.js service. Log HTTP requests automatically, avoid logging in tests and prettify the JSON logs.

  • Node.js
  • Express.js
  • TypeScript
  • Pino

• Advancing your company as a Software Engineer

  Process Mar 7, 2022 <100 views

  Learn how to make technical and organizational advancements as a software engineer. Reflecting on experiences of 12 successful and 3 unsuccessful advancements.

• OpenAPI input validation in Express.js

  Node.js Feb 16, 2022 3016 views

  Learn how to validate inputs with an OpenAPI spec in a TypeScript Express.js service. Write tests for the input validation and return meaningful HTTP errors.

  • Node.js
  • Express.js
  • TypeScript
  • OpenAPI

• Testing Express.js endpoints with supertest

  Node.js Feb 11, 2022 2249 views

  Learn to write Jest unit tests with supertest to test Express.js controllers in a TypeScript Node.js service.

  • Node.js
  • TypeScript
  • Express.js
  • Jest

• Organizing Express.js endpoints

  Node.js Feb 9, 2022 1402 views

  Learn how to organize the endpoints in a TypeScript Express.js service. Why a REST resource should have its own DAO and why you don't need three layers.

  • Node.js
  • TypeScript
  • Express.js

• About the Node.js series

  Node.js Feb 7, 2022 722 views

  In a series of blog posts, I'm going to describe an opinionated Node.js microservice architecture. Let me tell you about the why, what and how of this series.

  • Node.js
  • TypeScript
  • Express.js

• 2031 - A Software Engineering Utopia

  Process Jan 31, 2022 <100 views

  In a utopia of open APIs, open SaaS apps, funded open-source and an open cloud platform, we join Naomi, Javier and Kalina developing a new product.

• Working as a Senior Software Engineer

  Process Jan 26, 2022 <100 views

  Learn how to maximize your impact as a Senior Software Engineer. How to move your focus from contributing code towards helping your team succeed.

• Building a 1000 line Java program in 6 lines of Haskell

  Coding Jan 15, 2022 <100 views

  Let's disassemble an overly expressive six-line algorithmical Haskell program. I walk you through all the tricks, weirdness and beauty.

  • Haskell

• Identifying bad code with function usage patterns

  Coding Jan 13, 2022 <100 views

  Learn how to look at the call patterns of functions to identify code smells and refactor bad Java, TypeScript and JavaScript code.

  • JavaScript

• Implementing a light/dark mode toggle with pure JS/CSS

  Coding Jan 4, 2022 1249 views

  Learn how to implement a minimal light/dark mode toggle in Eleventy with pure JavaScript and CSS.

  • Eleventy
  • JavaScript

• How future languages will prevent Log4Shell

  Coding Dec 22, 2021 <100 views

  Learn how modern programming languages like Unison and Koka avoid vulnerabilities like Log4Shell in Java by preventing third-party code from executing side-effects.

  • Java

• Scrum As Code

  Process Dec 16, 2021 <100 views

  Learn how to represent Scrum as code and do product management in a git repository. Use CI and CD and finally be able to get rid of Jira.

  • Eleventy

• The One-Hour Interview Process

  Process Dec 14, 2021 <100 views

  Learn how to interview software engineering applicants. Without at-home assignments. Within an hour of interviewing. Includes TypeScript, Java and SQL examples.

  • Java
  • TypeScript

• Avoid Runtime Errors with Optionals

  Coding Aug 19, 2019 <100 views

  Learn how to use Optionals properly with flatMap avoiding null pointer exceptions.

  • Java