Khalil Stemmler | Advanced TypeScript & Node.js best practices for large-scale applications

My book on Node.js / TypeScript software design and architecture just pre-launched 📕 (%33 off)!

SOLID: The Software Design & Architecture Handbook

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I'm Khalil. I teach advanced TypeScript & Node.js best practices for large-scale applications. Learn to write testable, flexible, and maintainable software.

I create courses, books, and articles for aspiring developers on Enterprise Node.js, Domain-Driven Design, GraphQL, and writing testable, flexible JavaScript.

Recent Articles

How to Test Code Coupled to APIs or Databases Test-Driven Development

In the real-world, there's more to test than pure functions and React components. We have entire bodies of code that rely on datab...

How to Mock without Providing an Implementation in TypeScript Test-Driven Development

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Having to provide an implementation everytime you create a test double leads to brittle tests. In this post, we learn how to creat...

When to Use Mocks: Use Case Tests Test-Driven Development

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Mocking gets a pretty bad rap. However, if you're building an application using object-oriented programming and you're making use ...

Why I Recommend a Feature-Driven Approach to Software Design Software Design

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Features represent the essential complexity of software design. It's the complexity that can't be avoided. Everything else — the l...

Introduction to Test-Driven Development (TDD) with Classic TDD Example Test-Driven Development

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The best thing tests give us is "feedback". Feedback as to if our designs are good, if there are bugs, and if we're making progres...

GraphQL Schemas vs. RESTful DTOs GraphQL

graphql architecture software design restful apis dto

GraphQL schemas serve a similar purpose to RESTful DTOs. One of the main differences is tooling. In this post, I aim to strengthen...

Enforcing Coding Conventions with Husky Pre-commit Hooks Tooling

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In this guide, we'll learn how to setup Husky to prevent bad git commits and enforce code standards in your project.

Domain-Driven GraphQL Schema Design | Enterprise GraphQL GraphQL

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A GraphQL schema is a declarative, self-documenting, organization-wide API. It's pretty important to spend a little bit of time on...

How Apollo REST Data Source Deduplicates and Caches API calls [Deep Dive]GraphQL

apollo server graphql

Apollo's REST Data Source does a lot more than you'd think behind the scenes, and that's why it's recommended instead of using a w...

How to Setup a TypeScript + Node.js Project TypeScript

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In this guide, we walk through the process of creating a TypeScript project from scratch with cold-reloading, and scripts for buil...

Where Do Domain Events Get Created? | Domain Driven Design w/ TypeScript Domain-Driven Design

ddd domain entities software design domain events

In this post, I explain how good ol' fashioned encapsulation + TypeScript getters and setters enable us to effectively create Doma...

My book on Node.js / TypeScript software design and architecture just pre-launched 📕 (%33 off)!

SOLID: The Software Design & Architecture Handbook

Presale $29.99

Recent Blogs

Existential State Machines

May 24th, 2021

Originally published in volvox vault's issue on metamorphosis. Someone said I was a writer the other day. When the hell did that happen…

What Would Albert Camus Think About Software Development?

Apr 26th, 2021

Albert Camus was a French philosopher most well known for his ideas about absurdism. Sometimes regarded as an existentialist philosopher…

Transcribing Video With DDD Discussion | Domain Driven Design w/ TypeScript

Feb 22nd, 2021

I'm always interested in what blog readers are building using Domain-Driven Design and Clean Architecture practices. In this post, I'd like…

5 Ways to Manage Lambda Cold Starts

Jun 27th, 2020

In this article, you will learn how cold start issues occur, what factors contribute to cold starts, and how to manage Lambda cold starts…

Recently Edited Wikis

Coupling, Cohesion & Connascence

Last updated Sep 8th, 2021

object-oriented design software design

The foundational measurements of structural software quality

Test Doubles

Last updated Sep 7th, 2021

test doubles mocks stubs spies dummies fakes testing

A test double is a generic term to refer to any object that stands in for a production one during testing