Primitives in TypeScript

primitves.ts

let message: string = "Hello World"; // string type variable

let myNum: number = 42; // number type variable

let isReal: boolean =  true; // boolean type variable

let special: any = "Any type"; // any type variable

special = 13;  // any type doesn't cause any type checking errors

// Arrays

let numList: number[] = [1, 3, 5, 7] // a number array

let strList: string[] = ["Luke", "I", "am", "your", "father"] // a string array

// Functions


//This function takes two string types as input and returns a string output

function greeting(firstName: string, lastName: string): string {
    return firstName + lastName
}

let fullName = greeting("Han", "Solo")

console.log(fullName)

// Anonymous functions

// Inferred type
const names = ["Stark", "Potts", "Parker"];

// Contextual typing for arrow functions
names.forEach((s) => {
    console.log(s.toUpperCase());
});

// Tuples -  Special Arrays with fixed type elements

const universe: [number, string] = [1, "Marvel"];

// Enum type

enum Seasons { SUMMER, WINTER, SPRING, AUTUMN };

// can be accessed as

console.log(Seasons.WINTER)

// Unions

let data:(number | string) = 99;

data = "ninety nine"    //valid because it is a union