🎯 Basics & Type Declarations

• let a: string, b: any — Basic type annotations

• Literal types: let dog = { id: 1 } → { id: number }

• Type alias: type User = { id: number }

• Interface (Extensible):

  interface Influencer extends User { 
  	budget: number 
  }
  

🧩 Special Types & Modifiers

• null is a subtype of all types: let a: number = null
• never type: type Tree = { flesh: never }
• readonly properties: type User = { id: readonly string }
• unknown : unlike any, it has to be asserted before use.
• params: function fn(x? : number = 10) {}

🔁 Enums

enum UI { React, Vue, Angular }
let z = UI.Angular // 2

🎭 Type Assertions

let x = y as string
ele!.focus() // non-null assertion

⛓️ Intersection & Union Types

type Cat = { name: string }
type Domestic = { owner: string }
let kitty: Cat & Domestic //extends Both

let x: boolean | string // one of list

📦 Tuples & Constants

let p: [string, number] //fixed length typed array
let k = 2, v = true
let z = [k, v] as const // [2, true] <-- most narrow type possible

🛠️ Declarations & Generics