leetcode 4. 编写一个函数createCounter的

编写一个函数createCounter。它应该接受一个初始整数init。它应该返回一个具有三个函数的对象。
这三个功能是：
increment（）将当前值增加1，然后返回。
递减（）将当前值减少1，然后返回。
reset（）将当前值设置为init，然后返回。

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"

解决：

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

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

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

 /**
 https://leetcode.com/problems/counter-ii/solutions/3495319/2665-counter-ii-level-up-your-javascript-skills-with-these-intuitive-implementations/?envType=study-plan-v2&envId=30-days-of-javascript
  */

知识点：
https://leetcode.com/problems/counter-ii/solutions/3495319/2665-counter-ii-level-up-your-javascript-skills-with-these-intuitive-implementations/?envType=study-plan-v2&envId=30-days-of-javascript