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'use strict';

// Objects

// one of the JavaScript's data types.

// a collection of related data and/or functionality.

// Nearly all objects in JavaScript are instances of Object

// object = { key : value };

// 1. Literals and properties

const obj1 = {}; // 'object literal' syntax

const obj2 = new Object(); // 'object constructor' syntax

function print(person) {

console.log(person.name);

console.log(person.age);

}

const ellie = { name: 'ellie', age: 4 };

print(ellie);

// with JavaScript magic (dynamically typed language)

// can add properties later

ellie.hasJob = true;

console.log(ellie.hasJob);

// can delete properties later

delete ellie.hasJob;

console.log(ellie.hasJob);

// 2. Computed properties

// key should be always string

console.log(ellie.name); // 코딩하는 그 순간, 키에 해당하는 값을 받아오고 싶을 때

console.log(ellie['name']); // 우리가 정확하게 어떤 키가 필요한지 모를 때! 즉, 런타임에서 결정될 때

ellie['hasJob'] = true;

console.log(ellie.hasJob);

function printValue(obj, key) {

console.log(obj[key]);

}

printValue(ellie, 'name');

printValue(ellie, 'age');

// 3. Property value shorthand

const person1 = { name: 'bob', age: 2 };

const person2 = { name: 'steve', age: 3 };

const person3 = { name: 'dave', age: 4 };

const person4 = new Person('elile', 30);

console.log(person4);

// 4. Constructor Function

function Person(name, age) {

// this = {};

this.name = name;

this.age = age;

// return this;

}

// 5. in operator: property existence check (key in obj)

console.log('name' in ellie);

console.log('age' in ellie);

console.log('random' in ellie);

console.log(ellie.random);

// 6. for..in vs for..of

// for (key in obj)

console.clear(); // 이전 로그 기록 지우기

for (let key in ellie) {

console.log(key);

}

// for (value of iterable)

const array = [1, 2, 4, 5];

for (let value of array) {

console.log(value);

}

// 7. Fun cloning

// Object.assign(dest, [obj1, obj2, obj3...])

const user = { name: 'ellie', age: '20' };

const user2 = user;

console.log(user);

// old way

const user3 = {};

for (let key in user) {

user3[key] = user[key];

}

console.clear();

console.log(user3);

const user4 = Object.assign({}, user);

console.log(user4);

// another example

const fruit1 = { color: 'red' };

const fruit2 = { color: 'blue', size: 'big' };

const mixed = Object.assign({}, fruit1, fruit2);

console.log(mixed.color);

console.log(mixed.size);