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YCM Jason
Codes

I cook delicious TypeScript & JavaScript nuggets.

Short videos, long-form articles, and small open-source tools, mostly TypeScript, JavaScript, and the web.

Watch YouTube Read dev.to Code GitHub

Latest video

New on YouTube

The most recent upload from the channel.

Video thumbnail: Introducing ts-migrating: Upgrade TSConfig Progressively

Introducing ts-migrating: Upgrade TSConfig Progressively

NEW 20 Jun 2025 YouTube

Your code: powerful, but not clean. Here's why

7 MODERN IIFE TRICKS IN 10 MINUTES

TRY {} CATCH {} ‒ FIXED! (with a surprisingly old trick)

Live Coding: Recreating Vue's Reactivity System @ Vue.js Slovenia - YCMJason

Vue 3 Reactivity Reimagined - Live Coding @ Vue.js London Meetup 13 - Jason Yu

All videos YouTube

Speaking

On stage

Conference and meetup talks, mostly live-coding Vue internals from scratch.

Recreating Vue's Reactivity System Vue.js Slovenia · 2023 slides ↗

Vue 3 Reactivity Reimagined Vue.js London Meetup · 2019 slides ↗

The New Composition API Vue.js London Conf · 2019 slides ↗

Vue without View: Renderless Components Vue.js London Meetup · 2019 slides ↗

Building a Simple Virtual DOM from Scratch Manchester Web Meetup · 2018 slides ↗

Writing

Deep-dives and quick tips. The number is the read time, in minutes.

TypeScript Mutually Exclusive Unions: From `?: never` to `ExclusifyUnion` 3 min Nov 2025 ♥ 2 #typescript Introducing @ts-migrating: The Best Way To Upgrade Your TSConfig 3 min Jun 2025 ♥ 54 #typescript 7 Modern Use Cases of IIFE 7 min May 2025 ♥ 16 #javascript#typescript#webdev TRY {} CATCH {} ‒ FIXED! (with a surprisingly old trick) 3 min May 2025 ♥ 8 #javascript#typescript I Recreated Tom Riddle’s Diary, But Used My Soul Instead 👻 2 min Feb 2025 ♥ 2 #webdev#ai Advanced Typescript: Typing Partially Applicable Functions 12 min Jun 2023 ♥ 12 #typescript#functional Detecting barcode from the browser!!! 3 min Nov 2021 ♥ 47 #webdev#javascript#tutorial

All posts dev.to

Open source

Tools I shipped

Small, sharp tools I built and gave away.

ts-migrating ycmjason/

Upgrade your tsconfig progressively, adopt stricter compilerOptions one file at a time.

TypeScript ★ 68 acme fishballapp/

A zero-dependency, runtime-agnostic ACME (Let’s Encrypt) client for issuing TLS certificates.

TypeScript ★ 37 inquirer-cli fishballapp/

Run Inquirer.js prompts straight from npx, no install.

JavaScript ★ 3 keyboard-keyboard ycmjason/

An interactive keyboard you play with your keyboard.