CounterII.ts

/* 

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"

*/


type Counter = {
    increment: () => number,
    decrement: () => number,
    reset: () => number,
}

function createCounter(init: number): Counter {
    let val = init;
    return {
        increment() {
            return ++val;
        },
        decrement() {
            return --val;
        },
        reset() {
            val = init;
            return val;
        },
    };
};

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