04_counter2.js

// Question Link: https://leetcode.com/problems/counter-ii/?envType=study-plan-v2&envId=30-days-of-javascript
// Solution Link: https://leetcode.com/problems/counter-ii/solutions/5424118/easty-javascript-solution-using-arrow-function-time-space-complexity-o-1/

/*
2665. Counter II

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.
 
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
 
Constraints:
-1000 <= init <= 1000
0 <= calls.length <= 1000
calls[i] is one of "increment", "decrement" and "reset"
*/



/**
 * @param {integer} init
 * @return { increment: Function, decrement: Function, reset: Function }
 */
var createCounter = function(init) {
    let num = init;

    return {
        increment: () => {
            return ++num;
        },
        decrement: () => {
            return --num;
        },
        reset: () => {
            num = init;
            return num;
        }
    }
};

/**
 * const counter = createCounter(5)
 * counter.increment(); // 6
 * counter.reset(); // 5
 * counter.decrement(); // 4
 */