# 연산자 boolean

```javascript
//false : 0, -0 (0은 fasle), '' , null undefined -> 비어있는 값은 다 false
// true : -1  (0을 제외한 숫자 true)  '값이 있는 문자' , [ 비어있는 배열]

let num = 9;

if(num){ 
  console.log(num); // 9
}

num && console.log(num); // 9 && -> 앞이 true여야 실행이됨 

let obj = {
    name: 'ellie',
    age: 20
};

if(num){ 
  console.log(obj.name); // ellie
}

obj && console.log(obj.name); // ellie
// -> if와 &&연산자를 쓰는것은 동일한 역활을 한다.
```


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