문제
Write a function createCounter. It should accept an initial integer init. It should return an object with three functions.
The three functions are:
- increment() increases the current value by 1 and then returns it.
- decrement() reduces the current value by 1 and then returns it.
- reset() sets the current value to init and then returns it.
출력 예시
Example 1:
Input: init = 5, calls = ["increment","reset","decrement"]
Output: [6,5,4]
Explanation:
const counter = createCounter(5);
counter.increment(); // 6
counter.reset(); // 5
counter.decrement(); // 4
Example 2:
Input: init = 0, calls = ["increment","increment","decrement","reset","reset"]
Output: [1,2,1,0,0]
Explanation:
const counter = createCounter(0);
counter.increment(); // 1
counter.increment(); // 2
counter.decrement(); // 1
counter.reset(); // 0
counter.reset(); // 0
풀이
/**
* @param {integer} init
* @return { increment: Function, decrement: Function, reset: Function }
*/
var createCounter = function(init) {
let i = init
return {
increment: function() {
return ++i
},
decrement: function() {
return --i
},
reset: function() {
return i = init
}
}
};- return하기 전에 값이 증가 → 전위연산자 사용
