TypeScript Coffee

What If Your AI Agent Never Had to Leave the Browser? (Demo 🚀)

I haven't written anything lately because, honestly, I just didn't have the headspace for it. There... Read More

How Do We Extract the “Why” from a PR into a CHANGELOG with Jev? 🤔

Hoi hoi! 👋 I'm @nyaomaru, a frontend engineer currently building an AI-assisted CHANGELOG generator... Read More

TypeScript Compiler API: Preserving Child Node Narrowing in Reusable Type Guards 🔧

Hoi hoi! 👋 I'm @nyaomaru, a frontend engineer exploring new possibilities with Jev 😸 (I'm also... Read More

Why Your TypeScript Code Still Crashes in Production

A practical visual guide to the TypeScript mental model. Discover why types vanish at runtime, how structural typing works, and how to write clean, type-safe code that never crashes in production. Read More

Your Type Guard Can Silently Drift from Your TypeScript Type 🔧

Hoi hoi! 👋 I'm @nyaomaru, a frontend engineer just back from a short vacation on Texel, a small... Read More

Migrating a Real TypeScript OSS Library from tsup to tsdown 🔧

The config migration was small. Preserving the package contract was the interesting part. Hoi hoi!... Read More

"we should go out this weekend": I built a Discord member that holds the clock until we're outside

This is a submission for the Hacktoberfest Open-Source AI Challenge Week 1: Touch Grass TL;DR.... Read More

Jev vs Claude: Who Wins?

I did not need Jev to beat Claude or Kimi on a benchmark. I needed to know whether I could trust it... Read More

NestJS Testing Module: Provider Overrides (with Cheat Sheet)

A complete guide to NestJS's testing module: how overrideProvider really wires mocks, why get() fails on scoped providers, and using useMocker. Read More

AsyncLocalStorage vs Request-Scoped Providers: The DI Trap That Taxes Latency

Here's a logger. It's a dozen lines and it looks completely harmless: request-logger.ts import {... Read More

I missed Go's `if err != nil`, so I built errval for TypeScript

I write mostly TypeScript and some Go. When I switch back from Go, I miss explicit error returns. A... Read More

I Turned My Editor Into a Pokémon World That Levels Up When I Actually Ship

Repo: https://github.com/UribeJr/pokedev Most editor pets are wallpaper. Cute? Sure. Connected to... Read More

I Killed My Electron App Twice to Test Crash Recovery

"We have crash recovery" is an easy thing to claim. I wanted to know what happens if the process... Read More

TypeScript 7 Is Up to 10x Faster. Should You Upgrade Now?

Benchmark TypeScript 7 safely, compare real project results, and find compatibility problems before changing your main branch. Read More

🪪 Avatar RS: Very Efficient Avatar Components for WASM Frameworks

Bien le bonjour 👋! Every WASM app eventually needs an avatar. Profile pictures, user cards,... Read More

NestJS Guards: CanActivate, ExecutionContext & Reflector

A complete guide to NestJS guards: how CanActivate, ExecutionContext, and the Reflector decide who reaches your route handler, with a cheat sheet. Read More

How to Build a Task Management App with React & TypeScript

Hey everyone, it's Sadee! If you've ever wanted to build a cool task board where you can move... Read More

A browser arcade in plain TypeScript: 8 classic games, 35 kB, no framework

Play it: https://minjia-hu.github.io/retro-arcade/ Source:... Read More

What Protobuf descriptors don't tell you: building a generic mock generator

I built a library that generates mock data for any Protobuf message without per-message code. The schema walk was the easy part — here are the four things that actually bit me. Read More

Three ways I miscounted my own AI agents, and what the transcripts actually say

Claude Code writes a JSONL transcript for every session, and another one for every subagent it... Read More

I added a type-checked pipeline operator to TypeScript — including TSX

A proof-of-concept TypeScript compiler with a pipeline operator. I searching testers and... Read More

Inside TypeScript 7's Go Port: Designing Typed AST Nodes Without a Giant Struct

A step-by-step look at TypeScript 7's Go AST design: shared node data, syntax-specific data, discriminated unions, and a small Go implementation. Read More

MedusaJS Dropped the Foreign Keys Between Its Modules: The defineLink Gamble

MedusaJS 2.0 did something that would get a junior engineer's pull request rejected on sight: it... Read More

Never Execute the Translation: Build Language-Safe Slash Commands for Tencent RTC Chat

Build a reproducible TypeScript command boundary for a multilingual social-messaging app. Original messages may create moderation reports, translated text may help people read them, and only a human reviewer may decide the outcome. Read More