Basic Types 🧱

// A variable's TYPE fixes what kind of value it can hold.
// In TypeScript you can write the type after a colon:  let name: string = "Alice";
// The console.logs below run as plain JavaScript so you can see the values.

// string — text, in "double" or 'single' quotes or `backticks`
let firstName = "Alice";              // type: string
let greeting = `Hello, ${firstName}!`; // backticks let you embed ${...}
console.log(greeting);                // Hello, Alice!

// number — ONE type for integer
...

// 🎯 YOUR TURN — replace each ___ then press "Try it Yourself".

// 1) A string called "city" set to a city name
let city = ___;        // 👉 text in "double quotes"

// 2) A number called "year" set to the current year
let year = ___;        // 👉 a whole number, e.g. 2026

// 3) A boolean called "isOpen" set to true
let isOpen = ___;      // 👉 true or false (no quotes)

// These already work once your variables exist:
console.log(`In ${year}, the shop in ${city} is open: ${isOpen}`);

// ✅ E
...

// === Arrays — many values of the SAME type ===
// In TypeScript:  let scores: number[] = [95, 87, 92];
// The "number[]" means "an array where every element is a number".
let scores = [95, 87, 92];
console.log("scores:", scores);          // scores: [ 95, 87, 92 ]
console.log("first:", scores[0]);        // first: 95
console.log("how many:", scores.length); // how many: 3

let names = ["Alice", "Bob"];            // string[]
names.push("Charlie");                   // adding another string is 
...

// 🎯 YOUR TURN — fill in the blanks marked with ___

// 1) An array of three numbers (the type would be number[])
let temps = ___;          // 👉 e.g. [18, 21, 19]

// 2) Add one more reading to the end of the array
temps.push(___);          // 👉 any number, e.g. 22

// 3) A tuple describing a product: [name (string), price (number)]
let product = ___;        // 👉 e.g. ["Coffee", 2.5]

console.log("readings:", temps);
console.log(`${product[0]} costs £${product[1]}`);

// ✅ Expected output (e
...

// === any — turns OFF type checking (use as a last resort) ===
// "any" tells TypeScript "trust me, don't check this".
// It compiles, but you lose every safety net:
let data = 42;
data = "hello";   // with type 'any' this is allowed
data = [1, 2, 3]; // ...and so is this
console.log("data is now:", data); // data is now: [ 1, 2, 3 ]
// The danger: data.foo.bar would COMPILE but 💥 crash at runtime.

// === unknown — the SAFE alternative to any ===
// You CAN store anything in an 'unknown', but
...