every frontend concept
has a git blame.

why hooks exist. why the virtual DOM exists. why hydration is weird. we dig through the commit history of ideas so you don't have to.

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status: senior engineer reviewing the PR… from the keyboard

usestate.tscommit a3f9c21

12class Counter extends React.Component {

13- this.state = { count: 0 }

14- this.setState({ count: count + 1 })

13+ const [count, setCount] = useState(0)

14+ setCount(count + 1)

15}

why: class state meant logic tied to a lifecycle you didn't choose. hooks let state live in a function, so you could reuse it without wrapping everything in a class.

recent commits

4 concepts dissected this week

#b7e4c12build-tools

bundlers, ES modules, webpack — I ran npm run dev without knowing this

import './App.css' shouldn't work. it does because a bundler is lying for you. ES modules, webpack loaders vs plugins, how vite actually starts in 300ms — the version I wish I'd read before touching webpack.config.js.

+ ESM graph, loaders, vite on-demand- mystery webpack.config, 'just wait for compile'

#e3a91d0build-tools

npm, pnpm, Turbopack — I mixed these up for way too long

npm install is slow? use pnpm. dev server still slow? that's not pnpm's job. turbopack, vite, webpack — different layer entirely. wrote this after realising I'd been copy-pasting commands without knowing what they fix.

+ pnpm store, turbopack dev, lockfiles- phantom deps, webpack cold start

#c4e8b72browser

localhost, ngrok, and IP — why your friend can't open your dev server

localhost works on your machine and nowhere else. NAT blocks the public internet. ngrok tunnels through. here's the networking cheat sheet every frontend dev pretends they already know.

+ loopback, NAT, tunnel- "just share localhost"

#f8c2a19hooks

useSyncExternalStore — when the store lives outside React

concurrent rendering landed, the external store flipped mid-render, and the UI tore. this hook is the bridge Redux and Zustand already use under the hood — here's why it had to exist.

+ useSyncExternalStore, getServerSnapshot- useEffect subscribe hacks, torn UI

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every frontend concepthas a git blame.