fundamentals
Installation
SKILL.md
JavaScript Fundamentals Skill
Quick Reference Card
Variable Declaration
const PI = 3.14159; // Immutable binding (preferred)
let count = 0; // Reassignable
var legacy = "avoid"; // Function-scoped (avoid)
8 Data Types
| Type | Example | typeof |
|---|---|---|
| String | "hello" |
"string" |
| Number | 42, 3.14, NaN |
"number" |
| Boolean | true, false |
"boolean" |
| Null | null |
"object" |
| Undefined | undefined |
"undefined" |
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