TypeScript Crash Course

This is meant to be a basic introduction to common types used in TypeScript. This is not necessarily releated to React but will be used as React files are typed.

const myName: string = 'Aryan';
const myAge: number = 25; // I swear 🤥:
// array of type
const myFavoriteLanguages: string[] = ['JavaScript', 'Python', 'Java'];
// string literals (must be one of these EXACT values)
const seasons: 'summer' | 'fall' | 'winter' | 'spring' = 'winter';
// object with specific properties
const car: {
  make: string;
  model: string;
  yearReleased: number;
  hasAirbags?: boolean; // the question mark means this property is optional
} = {
  make: 'Honda',
  model: 'Civic',
  yearReleased: 1994,
}; // fun fact, this was my first car!
// you can also define the type separately
type Car = {
  make: string;
  model: string;
  yearReleased: number;
  hasAirbags?: boolean;
};
const someFancierCar: Car = {
  make: 'Jaguar',
  model: 'XJ',
  yearReleased: 2019,
  hasAirbags: true,
};
// array of objects
const garage: Car[] = [car, someFancierCar];
// function without call signature
const callback: Function = () => 'ohai!';
// function with call signature
const callbackWithStrictSignature: (name: string) => string = () => `hai again, ${name}!`;