LocalStorage

ELI5 — The Vibe Check

LocalStorage is a simple key-value storage built into every browser that persists even after you close the tab. It's like a tiny notebook your website can write in. Perfect for remembering user preferences, theme choice, or a small shopping cart. Just don't put passwords in there.

Real Talk

LocalStorage is a Web Storage API that provides synchronous key-value storage in the browser with no expiration. Data persists across sessions and is scoped to the origin. Maximum size is ~5-10MB. Because it's synchronous and blocking, avoid large read/write operations that could cause jank.

Show Me The Code

// Save user preference
localStorage.setItem('theme', 'dark')

// Read it back
const theme = localStorage.getItem('theme') // 'dark'

// Remove it
localStorage.removeItem('theme')

// Clear everything
localStorage.clear()

When You'll Hear This

We store the selected language in localStorage.,LocalStorage is synchronous — don't write huge objects to it.,Clear localStorage in tests to avoid state bleed between test runs.