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// 1. String concatenation

console.log('my' + ' cat');

console.log('1' + 2);

console.log(`string literals: 1 + 2 = ${1 + 2}`);

// 2. Numeric operators

console.log(1 + 1); // add

console.log(1 - 1); // substract

console.log(1 / 1); // divide

console.log(1 * 1); // multiply

console.log(5 % 2); // remainder

console.log(2 ** 3); // exponentiation

// 3. Increment and decrement operators

let counter = 2;

const preIncrement = ++counter;

// counter = counter + 1;

// preIncrement = counter;

console.log(`preIncrement: ${preIncrement}, counter: ${counter}`);

const postIncrement = counter++;

// postIncrement = counter;

// counter = counter + 1;

console.log(`postIncrement: ${postIncrement}, counter: ${counter}`);

const preDecrement = --counter;

console.log(`preDecrement: ${preDecrement}, counter: ${counter}`);

const postDecrement = counter--;

console.log(`postDecrement: ${postDecrement}, counter: ${counter}`);

// 4. Assignment operators

let x = 3;

let y = 6;

x += y; // x = x + y;

x -= y;

x *= y;

x /= y;

// 5. Comparison operators

console.log(10 < 6); // less than

console.log(10 <= 6); // less than or equal

console.log(10 > 6); // greater than

console.log(10 >= 6); // greater than or equal

// 6. Logical operators: || (or), && (and), ! (not)

const value1 = true;

const value2 = 4 < 2;

// || (or), finds the first truthy value // 처음으로 true가 나오면 멈춘다. 어떤것이든 하나라도 트루면 나는 트루야.

// 코드지적질!! => 연산을 많이하는 함수를 호출하는 함수를 제일 앞에 두게 되면 안됨!! 심플한 벨류 아이들을 앞에 둬서 얘네들이 false일 때만 마지막에 마지못해서 호출하는게 제일 좋음.

// 즉, 복잡한 함수로 호출하는 아이들을 제일 뒤에다가 배치할 것!

console.log(`or: ${value1 || value2 || check()}`);

// && (and), finds the first falsy value

// 헤비한 오퍼레이션일수록 제일 뒤에서 체크하는 것이 좋음!

console.log(`and: ${value1 && value2 && check()}`);

// often used to compress long if-statement

// nullableObject && nullableObject.something

function check() {

for (let i = 0; i < 10; i++) {

//wasting time

console.log('😱');

}

return true;

}

// ! (not)

console.log(!value1);

// 7. Equality

const stringFive = '5';

const numberFive = 5;

// == loose equality, with type conversion

console.log(stringFive == numberFive);

console.log(stringFive != numberFive);

// === strict equality, no type conversion

console.log(stringFive === numberFive);

console.log(stringFive !== numberFive);

// object equality by reference

const ellie1 = { name: 'ellie' };

const ellie2 = { name: 'ellie' };

const ellie3 = ellie1;

console.log(ellie1 == ellie2);

console.log(ellie1 === ellie2);

console.log(ellie1 === ellie3);

// equality - puzzler

console.log(0 == false);

console.log(0 === false); // 불리언 타입이 아니기 때문에 false

console.log('' == false);

console.log('' === false); // 불리언 타입이 아니기 때문에 false

console.log(null == undefined); // true

console.log(null === undefined); // false

// 8. Conditional operators: if

// if, else if, else

const name = 'df';

if (name === 'ellie') {

console.log('Welcome, Ellie!');

} else if (name === 'coder') {

console.log('You are amazing coder');

} else {

console.log('unkwnon');

}

// 9. Ternary operator: ?

// condition ? value1 : value2;

console.log(name === 'ellie' ? 'yes' : 'no');

// 10. Switch statement

// use for multiple if checks

// use for enum-like value check

// use for multiple type checks in TS

const browser = 'IE';

switch (browser) {

case 'IE':

console.log('go away!');

break;

case 'Chrome':

case 'Firefox':

console.log('love you!');

break;

default:

console.log('same all!');

break;

}

// 11. Loops

// while loop, while the condition is truthy,

// body code is executed.

let i = 3;

while (i > 0) {

console.log(`while: ${i}`);

i--;

}

// do while loop, body code is executed first,

// then check the condition.

do {

console.log(`do while: ${i}`);

i--;

} while (i > 0);

// for loop, for(begin; condition; step)

for (i = 3; i > 0; i--) {

console.log(`for: ${i}`);

}

for (let i = 3; i > 0; i = i - 2) {

// inline variable declaration

console.log(`inline variable for: ${i}`);

}

// nested loops

for (let i = 0; i < 10; i++) {

for (let j = 0; j < 10; j++) {

console.log(`i: ${i}, j:${j}`);

}

}

// break, continue

// Q1. iterate from 0 to 10 and print only even numbers (use continue)

for (let i = 0; i < 11; i++) {

if (i % 2 === 0) {

continue;

}

console.log(`q1. ${i}`);

}

// Q2. iterate from 0 to 10 and print numbers until reaching 8 (use break)

for (let i = 0; i < 11; i++) {

if (i > 8) {

break;

}

console.log(`q2. ${i}`);

}