TS 타입 종류

// 타입 종류

// 문자
let str: string;
let red: string = "Red";
let green: string = "Green";
let myColot: string = `My color is ${red}`;
let yourColor: string = "Your color is" + green;

// 숫자
let num: number;
let integer: number = 6;
let float: number = 3.14;
let infinity: number = Infinity;
let nan: number = NaN;

// 불린
let isBoolean: boolean;
let isDone: boolean = false;

// Null / Undefined
let nul: null;
let und: undefined;
//console.log(null) -> 오류. null변수를 추가해줘야함.
console.log(und); //undefined출력

// 배열
const fruits: string[] = ["Apple", "Banana", "Cherry"];
const numbers: number[] = [1, 2, 3, 4, 5, 6, 7];
const union: (string | number)[] = ["Apple", 1, 2, "Banana", 3];

// 객체
const obj: object = {};
const arr: object = [];
const func: object = function () {};

const userA: {
  name: string;
  age: number;
  isValid: boolean;
} = {
  name: "Doocong",
  age: 22,
  isValid: true,
};
//+interface 사용!

// 함수
const add: (x: number, y: number) => number = function (x, y) {
  return x + y;
};
// const a: number = add(1, 2);

const hello1: () => void = function () {
  console.log("Hello world!");
};
const h: void = hello1();

// Any
let hello: any = "Hello world";
hello = 123;
hello = false;
hello = null;
hello = {};
hello = [];
hello = function () {};

// Unknown
const a: any = 123;
const u: unknown = 123;

const any: any = a;
const boo: boolean = a;
const num: number = a;
const arr: string[] = a;
const obj: { x: string; y: number } = a;

// Tuple
const Tuple: [string, number, boolean] = ["a", 1, false];
const users: [number, string, boolean][] = [
  [1, "Neo", true],
  [2, "Evan", false],
  [3, "Lewis", true],
];

// Void -> return이 없을 때 사용.
function hello(msg: string): void {
  console.log(`Hello ${msg}`);
}
const hi: void = hello("world");

// Never
// const nev: [] = [];
// nev.push(3);

// Union
let union: string | number;
union = "HEllo";
union = 123;
// union = false -> 오류

// Intersection
interface User {
  name: string;
  age: number;
}
interface Validation {
  isValid: boolean;
}
const doocong: User & Validation = {
  name: "doocong",
  age: 22,
  isValid: true,
};