class Car{  //새 클래스 Car를 만듦
            //아직 인스턴스는 만들어지지 않았지만 언제든 만들 수 있음
    constructor(){
    }
}

const car1 = new Car();
const car2 = new Car();

class car{
    constructor(make, model){
        this.make = make;
        this.model = model;
        this.userGears = ['p','n','r','d'];
        this.userGear = this.userGears[0];
    }
    shift(gear){
        if(this.userGears.indexOf(gear)<0)
            throw new Error(`Invalid gear:${gear}`);
        this.userGear = gear;
    }
}

const car1 = new car("kia", "chacha");
const car2 = new car("honda", "molla");
car1.shift('d');
car2.shift('r');
car1.userGear   //"d"
car2.userGear   //"r"
car1.make;  //"kia"
car1.model; //"chacha"

const obj = Symbol();
const o = {a:1, b:2, c:3, [obj]:4};
for(let prop in o){
    if(!o.hasOwnProperty(prop)) continue;
    console.log(`${prop}: ${o[prop]}`);
}
//a: 1
//b: 2
//c: 3

const SYM = Symbol();
const o = {a:1, b:2, c:3, [SYM]:4};
Object.keys(o).forEach(prop=>console.log(`${prop}: ${o[prop]}`));
//a: 1
//b: 2
//c: 3

const o = {apple:1, xochitl:2, balloon:3, guitar:4, xylophone:5};
Object.keys(o).filter(prop=>prop.match(/^x/)).forEach(prop=>console.log(`${prop}: ${o[prop]}`));
//xochitl: 2
//xylophone: 5

const arr = ["b", "c", "d"];
undefined
arr.push("e");  // (4) ["b", "c", "d", "e"]
arr.pop();  //"e", (3) ["b", "c", "d"]
arr. unshift("a");  //(4) ["a", "b", "c", "d"]
arr.shift();    //"a", (3) ["b", "c", "d"]

const arr = [1, 2, 3];
arr.concat(4, 5, 6);    //(6) [1, 2, 3, 4, 5, 6]
//arr는 바뀌지 않음

const arr=[1,2,3,4,5]; 
arr.slice(3);   //[4, 5]
arr.slice(2,4); //[3, 4]
arr.slice(-2);  //[4, 5]
arr.slice(1, -2);   //[2, 3]
arr.slice(-2,-1);   //[4]

const arr = [1,5,7];
arr.splice(1,0,2,3,4);  //[], (6) [1, 2, 3, 4, 5, 7]
arr.splice(5,0,6);  //[], (7) [1, 2, 3, 4, 5, 6, 7]
arr.splice(1,2);    //[2,3], (5) [1, 4, 5, 6, 7]
arr.splice(2,1,'a','b');    //[5], (6) [1, 4, "a", "b", 6, 7]

const arr = [1,2,3,4];
undefined
arr.copyWithin(1,2);    //(4) [1, 3, 4, 4]
arr.copyWithin(2,0,2);  //(4) [1, 3, 1, 3]
arr.copyWithin(0,-3,-1);    //(4) [3, 1, 1, 3]

const arr = new Array(5).fill(1);   //(5) [1, 1, 1, 1, 1]
arr.fill("a");  //(5) ["a", "a", "a", "a", "a"]
arr.fill("b", 1);   //(5) ["a", "b", "b", "b", "b"]
arr.fill("c", 2,4); //(5) ["a", "b", "c", "c", "b"]
arr.fill(5,5,-4);   //(5) ["a", "b", "c", "c", "b"]
arr.fill(5.5,-4);   //(5) ["a", 5.5, 5.5, 5.5, 5.5]
arr.fill(0,-3,-1);  //(5) ["a", 5.5, 0, 0, 5.5]

const arr = [1,2,3,4,5];
arr.reverse();  //(5) [5, 4, 3, 2, 1]
arr.sort(); //(5) [1, 2, 3, 4, 5]

const arr = [{name:"shin"},{name:"hollo"},{name:"ha"},{name:"ahmad"}];
arr.sort(); //arr에 변화 없음
arr.sort((a,b)=> a.name > b.name);
//{name: "ahmad"},{name: "ha"},{name: "hollo"},{name: "shin"}
//name프로퍼티의 알파벳 순으로 정렬
arr.sort((a,b) => a.name[1] < b.name[1]);
// {name: "hollo"},{name: "ahmad"},{name: "shin"},{name: "ha"}
//name 프로퍼티 두번째 글자의 알파벳 역순으로 정렬

const o = {name:"Jerry"};
const arr = [1,5,"a",o,true,5,[1,2],"9"];
arr.indexOf(5); //1
arr.lastIndexOf(5); //5
arr.indexOf({name:"Jerry"});    //-1

const arr=[{id:5, name:"shin"},{id:7, name:"hollol"}];
undefined
arr.findIndex(o => o.id ===5);  //0
arr.findIndex(o=>o.name==="hollol");    //1

const arr=[{id:5, name:"shin"},{id:7, name:"hollol"}];
arr.find(o => o.id ===5);   //{id: 5, name: "shin"}

const arr=[5,7,12,15,17];
arr.some(x=> x%2 === 0);    //true, 12가 짝수이기 때문
arr.every(x=> x%2 === 0);   //false

const cart = [{name:"book", price:123.5},{name:"tea", price:56.7}];
const names = cart.map(x=>x.name);  //(2) ["book", "tea"]
const items = ["candy","choco"];
const price = [2.25, 7.3];
const list = items.map((x, i) => ({name: x, price:price[i]}));
//list : [{name: "candy", price: 2.25},{name: "choco", price: 7.3}]

const arr = [5,7,2,4];
const sum = arr.reduce((a,x) => a += x, 0); //18
//0은 초기값, a의 초기값은 0이 된다.

const arr = [1, null, "hello", "world", true, undefined];
delete arr[3];
arr.join(); //"1,,hello,,true,"
arr.join("-");  //"1--hello--true-"
const html = '<ul><li>' + arr.join('</li><li>')+'</li><ul>';
// html : "<ul><li>1</li><li></li><li>hello</li><li></li><li>true</li><li></li><ul>"

$(document).ready(function(){
    var val = 50;   //특정 값 입력(퍼센트 계산이기 때문에 0~100 사이의 값 입력)
    var $circle = $('#svg .cir');   
    var r = $circle.attr('r');   //
    var per = ((100 - val) / 100) * Math.PI *r * 2; //호의 길이 계산
    $circle.css(
        strokeDashoffset: per
    ); //css에 offset 수치 입력
});

function hello(){
    return "Hello world!";
}
hello();   //"Hello world!"

const f = hello;
f();   //"Hello world!"

function avg(a, b){
    return (a+b)/2;
}
avg(5, 10);   //7.5

function f(x){
    return `f: x=${x}`;
}
f();   //"f: x=undefined"

function f(a,b = "blabla",c=3){
    return `${a} - ${b} - ${c}`;
}
f(5, 6, 7);   //"5 - 6 - 7"
f(5, 6);   //"5 - 6 - 3"
f(5);   //"5 - blabla - 3"
f();   //"undefined - blabla - 3"

const f1 = fuction() {return "hello";}
//또는
const f1 = () => "hello";
const f2 = function(name) {return `Hello, ${name}!`;}
//또는
const f2 = name => `Hello, ${name}!`;
const f3 = function(a, b) {return a+b};
//또는 
const f3 = (a, b) => a+b;

function avg(a, b){
    return (a+b)/2;
}
avg(5, 10);   //7.5
const avg = (a, b) => {
    return (a+b)/2
    };
avg(5, 10);   //7.5

//객체선언
const obj = {b:2, c:3, d:4};
//해체할당
const {a, b, c} = obj;
a;   //undefined : obj에는 a프로퍼티가 없음
b;   //2
c;   //3
d;   //ReferenceError : d는 정의되지 않음

const obj = {b:2, c:3, d:4};
let a, b, c;
{a, b, c} = obj;   //에러염
({a, b, c} = obj);   //동작함...??

const arr = [1,2,3];
let[x,y] = arr;
x;   //1
y;   //2
z;   //ReferenceError

const arr = [1, 2, 3, 4, 5];
let [x,y, ...rest] = arr;
x;   //1
y;   //2
rest;   //[3,4,5]

let a = 5, b = 10;
[a, b] = [b, a];
a;   //10
b;   //5

NaN === NaN   //false
NaN == NaN   //false

let NotNaN = "string";
isNaN(NotNan);   //true

let n = 0;
while(true){
    n += 0.1;
    if(n === 0.3) break;
}
console.log(`Stopped at ${n}`);

let n = 0;
while(true){
    n += 0.1;
    if(Math.abs(n-0.3) < Number.EPSILON) break;
}
console.log(`Stopped at ${n}`);   //Stopped at0.30000000000000004

 while(funds > 1 && funds < 100){
     let total = rand(1, funds);
    if(total === 13) {
        console.log("Unlucky! Skip this round....");
        continue;
    } 
    //플레이 구문
}

et arr = [1,2,3,4,5,6,7,8,9,10];
for(let n of arr){
    if(n === 5){
        break;
    }
	console.log(n);
}
//1
//2
//3
//4

let i = 0;
const arr = [1,2,3,4,5,6,7,8,9];
for(; i<arr.length; i++){
    if(arr[i] === 5) break;
}
if(i === arr.length) console.log('뭔지 모르겠다');
else console.log(`루프를 돌아서 마지막에 멈춘 수의 포지션은 ${i}입니다. `);
//루프를 돌아서 마지막에 멈춘 수의 포지션은 4입니다.

for (let i = arr.length-1; i>=0; i--){
    if(isPrime(arr[i])) arr.splice(i, 1);
}

var myArr = [1,2,3,4,5]
for (var i=0; i< myArr.length; i++){
	console.log(myArr[i]);
}

for (var i=0, max = myArr.length; i<max; i++){
	console.log(myArr[i]);
}

		
for(; var i = myArr.length; i--;){
	console.log(myArr[i]);
}

for(variable in object)
    statement

const player = { name : 'Thomas', rank : 'Midshipman', age:25}
for(let prop in player){
    if(!player.hasOwnProperty(prop)) continue;
    console.log(prop + ':' + player[prop]); 
}

"name:Thomas"
"rank:Midshipman"
"age:25"

for(variable of object)
    statement

const hand = [randFace(), randFace(), randFace()];
for(let face of hand)
    console.log(`you rolled...${face}!`);
//

const hand = [randFace(), randFace(), randFace()];
for (let i=0; i<hand.length; i++)
    console.log(`ROLL ${i+1} : ${hand[i]}`);

let iterable = [10, 20, 30];
for (let value of iterable) {
  console.log(value);
}
// 10
// 20
// 30

let iterable = "boo";
for (let value of iterable) {
  console.log(value);
}
// "b"
// "o"
// "o"

let iterable = new Map([["a", 1], ["b", 2], ["c", 3]]);
for (let entry of iterable) {
  console.log(entry);
}
// [a, 1]
// [b, 2]
// [c, 3]
for (let [key, value] of iterable) {
  console.log(value);
}
// 1
// 2
// 3