TYPES

Example of TYPES:

// string
let myName: string = 'Max';
// myName = 28;

// number
let myAge: number = 27;
// myAge = 'Max';

// boolean
let hasHobbies: boolean = false;
// hasHobbies = 1;

// assign types
let myRealAge: number;
myRealAge = 27;
// myRealAge = '27';

// array
let hobbies: any[] = ['Cooking', 'Sports'];
hobbies = [100];
// hobbies = 100;

// tuples
let address: [string, number] = ['Superstreet', 99];

// enum
enum Color {
  Gray, // 0
  Green = 100, // 100
  Blue = 2, // 2
}
let myColor: Color = Color.Blue;
console.log(myColor);

// any
let car: any = 'BMW';
console.log(car);
car = { brand: 'BMW', series: 3 };
console.log(car);

// functions
function returnMyName(): string {
  return myName;
}
console.log(returnMyName());

// void
function sayHello(): void {
  console.log('Hello!');
}

// argument types
function multiply(value1: number, value2: number): number {
  return value1 * value2;
}
// console.log(multiply(2, 'Max'));
console.log(multiply(10, 2));

// function types
let myMultiply: (a: number, b: number) => number;
// myMultiply = sayHello;
// myMultiply();
myMultiply = multiply;
console.log(myMultiply(5, 2));

// objects
let userData: { name: string; age: number } = {
  name: 'Max',
  age: 27,
};
// userData = {
//     a: "Hello",
//     b: 22
// };

// complex object
let complex: { data: number[]; output: (all: boolean) => number[] } = {
  data: [100, 3.99, 10],

  output: function(all: boolean): number[] {
    return this.data;
  },
};
// complex = {};

// type alias

type Complex = { data: number[]; output: (all: boolean) => number[] };

let complex2: Complex = {
  data: [100, 3.99, 10],

  output: function(all: boolean): number[] {
    return this.data;
  },
};

// union types
let myRealRealAge: number | string = 27;
myRealRealAge = '27';
// myRealRealAge = true;

// check types
let finalValue = 30;
if (typeof finalValue == 'number') {
  console.log('Final value is a number');
}

// never
function neverReturns(): never {
  throw new Error('A new Erorr');
}

//Nullable Types
let canBeNull: number | null = 12;
canBeNull = null;

let canAlsoBeNull;
canAlsoBeNull = null;

let canThisBeAny = null;
canThisBeAny = null;