๐ฆ Day23
//
const member = [
{
name: "Tina",
age: 24,
gender: "female",
position: "Front-end"
},
{
name: "Rob",
age: 31,
gender: "male",
position: "Back-end"
},
{
name: "Hugh",
age: 28,
gender: "male",
position: "Dev-ops"
}
]
// ์ด๋ฆ์ด Hugh์ธ ๋ฉค๋ฒ์ position ๊ฐ ์์๋ด๊ธฐ
member[2].position
// Dev-ops
undefined
, null
, NaN
์ ์๋ฃํ//while๋ฌธ์ผ๋ก ๊ตฌ๊ตฌ๋จ ์ถ๋ ฅํ๊ธฐ
let i = 2;
let j = 1;
while(i<10){
while(j<10){
console.log(`${i} X ${j} = ${i*j}`)
j++
}
i++
j = 1
}
/*
2 X 1 = 2
2 X 2 = 4
2 X 3 = 6
2 X 4 = 8
2 X 5 = 10
2 X 6 = 12
2 X 7 = 14
2 X 8 = 16
2 X 9 = 18
3 X 1 = 3
3 X 2 = 6
3 X 3 = 9
3 X 4 = 12
3 X 5 = 15
3 X 6 = 18
3 X 7 = 21
3 X 8 = 24
3 X 9 = 27
4 X 1 = 4
4 X 2 = 8
4 X 3 = 12
4 X 4 = 16
4 X 5 = 20
4 X 6 = 24
4 X 7 = 28
4 X 8 = 32
4 X 9 = 36
5 X 1 = 5
5 X 2 = 10
5 X 3 = 15
5 X 4 = 20
5 X 5 = 25
5 X 6 = 30
5 X 7 = 35
5 X 8 = 40
5 X 9 = 45
6 X 1 = 6
6 X 2 = 12
6 X 3 = 18
6 X 4 = 24
6 X 5 = 30
6 X 6 = 36
6 X 7 = 42
6 X 8 = 48
6 X 9 = 54
7 X 1 = 7
7 X 2 = 14
7 X 3 = 21
7 X 4 = 28
7 X 5 = 35
7 X 6 = 42
7 X 7 = 49
7 X 8 = 56
7 X 9 = 63
8 X 1 = 8
8 X 2 = 16
8 X 3 = 24
8 X 4 = 32
8 X 5 = 40
8 X 6 = 48
8 X 7 = 56
8 X 8 = 64
8 X 9 = 72
9 X 1 = 9
9 X 2 = 18
9 X 3 = 27
9 X 4 = 36
9 X 5 = 45
9 X 6 = 54
9 X 7 = 63
9 X 8 = 72
9 X 9 = 81
*/
let arrFruit = ['apple', 'banana', 'mandarine','blueberries']
//forEach
arrFruit.forEach((fruit, idx) => console.log(idx, fruit))
/*
0 'apple'
1 'banana'
2 'mandarine'
3 'blueberries'
*/
// for ... in
// ๋ฐฐ์ด์ ๊ฐ ์ธ๋ฑ์ค๋ฅผ ์ํํ๋ฉฐ ์ธ๋ฑ์ค ์ถ๋ ฅ
for (var fruit in arrFruit){
console.log(fruit, arrFruit[fruit]);
}
/*
0 apple
1 banana
2 mandarine
3 blueberries
*/
//for ... of
// ๋ฐฐ์ด์ ๊ฐ ์ธ๋ฑ์ค ์ํํ๋ฉฐ ํด๋น ์ธ๋ฑ์ค์ ์์ ์ถ๋ ฅ
for (var fruit of arrFruit){
console.log(fruit);
}
/*
apple
banana
mandarine
blueberries
*/
function add(x, y){
// ์ฌ๊ธฐ์ x์ y๋ ๋งค๊ฐ๋ณ์(parameter)๋ผ๊ณ ํ๋ค. ์ธ๋ถ์์ ํจ์๊ฐ ํธ์ถ๋ ๋ ๋๊ฒจ๋ฐ๋ ์ธ์๋ฅผ ์ ๋ฌ๋ฐ๋ ์ญํ ์ ํ๋ค.
return x + y
}
add(3,5) // 8
// ์ฌ๊ธฐ์ 3,5๋ ์ ๋ฌ์ธ์(argument)๋ผ๊ณ ํ๋ค. ํจ์์ ์ด ๊ฐ์ด ๋๊ฒจ์ ธ์ ํจ์ ๋ด๋ถ ๊ณ์ฐ์์ด ์ํ๋๋ค.
function add(x,y){
return x+y
}
function mul(x,y){
return x*y
}
function cal(a,b){
return a(10, 10) + b(10, 10);
}
cal(add, mul) // ์ฝ๋ฐฑํจ์
function add(x,y){
return x+y
}
// ์์ addํจ์๋ฅผ ํ์ดํ ํจ์๋ก ํํ
let add = ((x,y) => x+y)
// ๊ธฐ๋ช
ํจ์
let aa = function sum(x, y) {
return x + y
}
// ์ต๋ช
ํจ์์ธ๊ฒ ๊ฐ์ง๋ง ๋ฐ๋
let bb = function(x, y) {
return x + y
}
// ES5์์๋ ๋น ๋ฌธ์์ด์ด์๋๋ฐ ES6์์ name ๊ฐ์ ๊ฐ์ง๋ ๊ฒ์ผ๋ก ๋ฐ๋์์ต๋๋ค.
let cc = (x, y) => x + y;
console.dir(function (x, y) {return x + y;})