optional property

// interface2.ts
// optional 은 ? 붙여주면 됨
interface Person2 {
  name: string;
  age?: number; 
}

function hello2(person: Person2): void {
  console.log(`안녕하세요! ${person.name}입니다.`);
}

hello2({ name:'Mark', age: 39 });
hello2({ name:'Anna' });

// interface2.js
"use strict";
function hello2(person) {
    console.log(`안녕하세요! ${person.name}입니다.`);
}
hello2({ name: 'Mark', age: 39 });
hello2({ name: 'Anna' });

// interface3.ts
// 어떠한 형태로든 출력할 수 있음
interface Person3 {
  name: string;
  age?: number;
  [index: string]: any  
}

function hello3(person: Person3): void {
  console.log(`안녕하세요! ${person.name}입니다.`);
}

const p31: Person3 = {
  name: "Mark",
  age: 39
};

const p32: Person3 = {
  name: "Anna",
  sisters: ["Luna", "Jennie"]
};

const p33: Person3 = {
  name: "James",
  father: p31,
  mother: p32
}

hello3(p33);

// interface3.js
"use strict";
function hello3(person) {
    console.log(`안녕하세요! ${person.name}입니다.`);
}
const p31 = {
    name: "Mark",
    age: 39
};
const p32 = {
    name: "Anna",
    sisters: ["Luna", "Jennie"]
};
const p33 = {
    name: "James",
    father: p31,
    mother: p32
};
hello3(p33);