string
let str: string;
let red: string = 'Red';
let green: string = 'Green';
let myColor: string = `My color is ${red}.`;
let yourColor: string = 'Your color is' + green + '.';
number
let num: number;
let integer: number = 6;
let float: number = 3.14;
let infinity: number = Infinity;
let nan: number = NaN;
boolean
let isBoolean: boolean;
let isDone: boolean = false;
let isGood: boolean = true;
Null / Undefined
let nu: null;
let undef: undefined;
nul = null;
배열
const fruits: string[] = ['Apple', 'Banana', 'Cherry'];
const numbers: number[] = [1, 2, 3, 4, 5, 6];
const union: (string|number)[] = ['Apple', 1, 'Banana', 2, 3, 'Cherry']
const onlyOne: ['only'] = ['only'];
객체
const obj: object = {};
const arr: object = [];
const func: object = function () {};
const userA: {
name: string;
age: number;
isValid: boolean;
} = {
name: 'sunkeydokey',
age: 26,
isValid: true,
};
interface User {
name: string;
age: number;
isValid: boolean;
}
const userB: User = {
name: 'sunny',
age: 23,
isValid: false,
};
const userC: User = {
name: 'sun',
age: 33,
isValid: false,
};
함수
const add: (x: number, y: number) => number = function (x, y) {
return x + y;
};
const newAdd = function (x: number, y: number): number {
return x + y;
};
function addThree(x: number, y: number, z: number): number {
return x + y + z;
}
const result: number = add(1, 2);
const sayHello: () => void = function () {
console.log('Hello');
};
const hello: void = sayHello();
Any
let anything: any = 'anything';
anything = 123;
anything = false;
anything = true;
anything = {};
anything = [];
anything = function () {};
const a: any = 123;
const any: any = a;
const boo: boolean = a;
const num: number = a;
const arr: string[] = a;
const obj: { x: string, y: number } = a;
Unknown
const u: unknown = 123;
const any: any = u;
const boo: boolean = u;
const num: number = u;
const arr: string[] = u;
const obj: { x: string; y: number } = u;
Tuple
const tuple: [string, number, boolean] = ['a', 1, false];
const users: [number, string, boolean][] = [
[1, 'Lee', true],
[2, 'Kim', false],
[3, 'Park', true],
];
Void
function helloWithMessage(msg: string): void {
console.log(`hello ${msg}`);
}
const hi: void = helloWithMessage('world');
Never
const nev: [] = [];
nev.push(3);
Union
let union: string | number;
union = 'Hi';
union = 12345;
Intersection
interface Customer {
name: string;
age: number;
}
interface Grade {
isVip: boolean;
}
const customerA: Customer & Grade = {
name: 'Kim',
age: 52,
isVip: true,
};