'[ ]'๋ฅผ ์ฌ์ฉํ์ฌ ๊ฐ์ ๋ฐฐ์ดํ ์ ์๋ค.
const dayOfWeek = ["Mon","Tue", "Wed", "Thu", "Fri", "Sat"];
console.log(dayOfWeek[2]);
dayOfWeek.push("Sun"); // ---------> ๋์ "sun"์ ์ถ๊ฐ
dayOfWeek[3] = "Mon"; // ---------> 4๋ฒ์งธ ๊ฐ์ ๋ฐ๊ฟ (0๋ถํฐ ์์)
console.log(dayOfWeek);
'{ }'๋ฅผ ์ฌ์ฉํ๊ณ ๊ฐ๊ฐ ํ์ํ Key์ ๊ฐ์ ์ค๋ค.
๋จ, ๊ฐ์ ์ฃผ๊ณ ๋์ ์ผํ(,)๋ ํ์.
๋ํ, ๋ฐ๋์ ํค์ ๊ฐ ์ฌ์ด์ ์ฝ๋ก (:) ์ฌ์ฉ.
const player = {
name: "soyeon",
age: 18,
points: 10,
fat: true,
};
console.log(player);
player.age = player.age +8;
console.log(player.age);
console.log(player);
player.fat = false;
console.log(player);
function sayHello(nameOfPerson, age){
console.log("Hello my name is " + nameOfPerson + " I'm " + age +"years old!");
}
sayHello("dal", 14);
sayHello("soyeon", 25);
sayHello("nico", 29);
function plus(a, b){
console.log(a + b);
}
function devide(a, b){
console.log(a / b);
}
plus(18, 27);
devide(15, 5);
const player = {
name: "soyeon",
sayHello: function (oneOtherName) {
console.log(oneOtherName);
console.log(document.getElementById("greeting").innerText);
//HTML -> <h1 id = "greeting"> HELLO! </h1>
console.log("Hello my name is " + oneOtherName + " I'm ");
},
age: 15
}
console.log(player.name);
player.sayHello("sysy"); // ------> ์ด๋ฆ ๋ณ๊ฒฝ ๊ฐ๋ฅ
console.log(player); // -------> ๋ณ๊ฒฝ๋ ์ด๋ฆ์ผ๋ก ๋์ด
const me = {
name: function (otherName){
console.log("Hello my name is " + otherName + ".");
},
age: function (otherAge){
console.log("I'm " + otherAge + " years old.");
},
}
console.log(me);
me.name("soyeon");
me.age(26);
const caculator = {
plus: function(a, b) {
console.log(a + b)
},
minus: function(a, b) {
console.log(a - b)
},
squa: function(a, b) {
console.log(a ** b)
},
div: function(a, b) {
console.log(a / b)
},
};
caculator.plus(2, 3);
caculator.minus(82432, 654);
caculator.squa(5, 3);
caculator.div(20, 4);
console.log๋ ๋จ์ํ ์ฝ์์ฐฝ์ ์์น๋ง ์
๋ ฅํด์ค ๋ฟ ๋ค๋ฅธ ์๋ฏธ๊ฐ ์๋ค.
(์๋ฐ์คํฌ๋ฆฝํธ ์ฝ๋์์๋ ๊ทธ ๊ฐ์ ๋ฐ๋ก ์ป์ ์ ์์)
๋ฐ๋ผ์ ์ฐ๋ฆฌ๋ ๋ณ์(const, let, var)์ function์ ํ ๋นํ์ฌ return์ ํตํด ๊ทธ ๊ฐ์ ๋ฐํํ์ฌ(?) ๊ฐ์ง ์ ์๋ค.
return์ ํตํด ๋ฐํ๋ function์ ๋์ด์ ์ฌ์ฉ ๋ถ๊ฐ!!
const age = 96;
function calculatekrAge(ageOfForeigner){
ageOfForeigner +2;
}
const krAge = calculatekrAge(age);
console.log(krAge); // output ------> undefined
const caculator = {
plus: function(a, b) {
return a + b;
},
minus: function(a, b) {
return a - b;
},
mult: function(a, b) {
return a ** b;
},
div: function(a, b) {
return a / b;
},
};
const plusResult = caculator.plus(2, 3); // output -----> 5
const minusResult = caculator.minus(645, plusResult); // output -----> (645-5) 640
const multResult = caculator.mult(minusResult, 2); // output -----> (640**2 604์ ์ ๊ณฑ) 409600
const divResult = caculator.div(minusResult, plusResult); // output -----> (640/5) 128
if๋ฌธ์ ์กฐ๊ฑด๋ฌธ์ ํตํด booleanํ์
์ผ๋ก ๋ฐํ๋๋ค.
parseInt()๋ ๋ฌธ์์ด๊ณผ ์ซ์๋ฅผ ๊ตฌ๋ณํ์ฌ ์ ์๋ก ๋ฐํํด์ฃผ๋ ํจ์.
isNaN()์ ๊ฐ์ด Not a Number์ธ์ง ์๋์ง ๊ตฌ๋ณํด์ฃผ๋ ํจ์.
else๋ ์ ํ์ฌํญ(์ฌ์ฉํด๋ ๋๊ณ , ์ํด๋ ๋จ)
"==="์ "๊ฐ๋ค"
"!=="์ "๋ค๋ฅด๋ค"
"&&"์ "๊ทธ๋ฆฌ๊ณ " => ๋ชจ๋ ์กฐ๊ฑด์ด true์ฌ์ผ true๊ฐ์ ๊ฐ์ง.
"||"๋ "๋๋" => ์ฌ๋ฌ ๊ฐ ์ค ํ๋๋ง true ๊ฐ์ ๊ฐ์ง๋ฉด true.
ย ย ย ย ย ย ย ย ย ย ย ย ย ย ย ย ย ย ย ย ย ย ๋ชจ๋ ๊ฐ์ด ๋ค false์ผ ๊ฒฝ์ฐ, false.
const age = parseInt( prompt("How old are you?") );
if(isNaN(age) || age < 0){
console.log("Please write a number.");
} else if(age < 18){
console.log("You are too young.");
} else if(age >= 18 && age <= 50){
console.log("Welcome Drinking World!")
} else{
console.log("Drinking is not good for your health.");
}