[TypeScript] 기본 타입 정리

숫자(Number)

let myNum: number = 6;

문자열(String)

let color: string = "pink";
color = 'red';

불리언(Boolean)

let isFinished: boolean = false;

배열(String)

let numberList: number[] = [1, 2, 3];
let stringList: string[] = ["1","2","3"];

튜플(Tuple)

let array: [string, number];
array = ["hello", 1]; //ok

열거 (Enum)

enum Color {Red, Green, Pink}
let myColor: Color = Color.Green;

enum Color {Red = 1, Green, Pink}
let myColor: Color = Color.Green;

enum Color {Red = 1, Green = 2, Pink = 4}
let myColor: Color = Color.Green;

Any

let idkType: any = 4;
idkType = "maybe a string instead";
idkType = false;

undefined

let a: undefined = undefined;

null

let b: null = null;

Void

// dont retrun anything

function hello():void {
	console.log('x')
}

//void를 써주지 않아도 됨
function hello() {
	console.log('x')
}

Never

// 함수가 절대 return 하지 않을 때

function hello():never {
	retrun X;
} // Error

function hello():never {
	throw new Error("xxx")
}

// Type이 두가지 이상일 때
function hello(name: string | number) {
	if(typeof name === "string"){
    	name
    } else if (typeof name === "number") {
    	name
    } else { // never never ever run
    	name // never never ever run
    } // never never ever run
}

unknown

let a: unknown;
let b = a + 1; // x

if(typeof a === 'number') {
	let b = a + 1;
}

readonly

const person : readonly [string, number, boolean] = ["Bibliya", 20, true];
person[0] = "BibliyaSeo"; // 실패 readonly는 변경 불가