# 2665. Counter II

###### tags: `leetcode 30 days js challenge` `Easy`

[2665. Counter II](https://leetcode.com/problems/counter-ii/)

### 題目描述

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.

### 範例

**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`
- `total calls not to exceed 1000`

### 解答

#### TypeScript

type ReturnObj = {
  increment: () => number;
  decrement: () => number;
  reset: () => number;
};

function createCounter(init: number): ReturnObj {
  let count = init;
  const increment = () => ++count;
  const decrement = () => --count;
  const reset = () => (count = init);

  return {
    increment,
    decrement,
    reset,
  };
}

> [name=Sheep][time=Sun, May 7, 2023]

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