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Examples & lessons
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Basics
Variables & types
TS
let / const and what each value evaluates to
Template strings
JS
Build strings with ${} interpolation
Numbers & Math
JS
Arithmetic, rounding, random
Arrays
Array basics
JS
push, length, indexing, slice
map / filter / reduce
JS
The three you'll use every day
Sorting
JS
Why sort() surprises people
Objects & data
Objects
JS
Access, spread, destructure
Map & Set
TS
The inspector shows these properly
JSON parse & stringify
JS
Text <-> objects
Functions
Functions & arrows
JS
Declare, call, default params
Closures
JS
Functions that remember state
Async
async / await
JS
Top-level await just works here
fetch an API
JS
Real network request
Playground (HTML/CSS/JS)
Build a list from data
</>
Render an array into the DOM
A CSS animation
</>
Keyframes + a pulsing box
Bouncing ball (canvas)
</>
requestAnimationFrame loop
npm packages
Import from npm
TS
Any package, via npm: specifiers
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GitHub
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Espresso
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Catppuccin Mocha
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Gruvbox
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Nord
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Show line numbers
Word wrap
Auto-evaluate on type
Inline values in playground