Whetstone

JavaScript & TypeScript Fundamentals

The language layer every other track assumes: choosing Map, Set, object or array (and what each costs), the shorthand syntax you read in review and what it expands to, equality and truthiness, narrowing unions instead of reaching for enums, and updating data without mutating the copy someone else still holds.

  1. 1. Maps, Sets, objects & arrays: choosing the collection

    Full · Intro · ~30 min
    • JavaScript
    • Map, Set & Collections

  2. 2. Shorthand syntax and what it expands to

    Full · Intro · ~30 min
    • JavaScript
    • Modern Syntax

  3. 3. Equality, truthiness, null and undefined

    Lesson · Core · ~30 min
    • JavaScript
    • TypeScript
    • Equality & Truthiness
    • null vs undefined

  4. 4. Narrowing, unions, and why not enums

    Full · Core · ~35 min
    • TypeScript
    • Narrowing & Unions
    • Enums

  5. 5. Immutable updates: change the data, not the copy

    Full · Core · ~35 min
    • JavaScript
    • Component State
    • Immutability