JS代码重构求助：如何在switch中嵌入函数精简计算器代码

当然可以通过整合运算逻辑和配置信息来精简switch语句里的重复代码，以下是两种适合初学者的改进思路：

方案一：用对象映射替代switch（最精简易维护） #

将所有操作的运算函数、提示文本、结果描述统一存入一个配置对象，直接通过操作编号获取对应配置，避免重复编写输入输出逻辑：

// 精简版基础运算计算器
const operations = {
  '1': {
    func: (a, b) => a + b,
    aPrompt: 'Enter the value for A: ',
    bPrompt: 'Enter the value for B: ',
    resultText: 'The addition result is'
  },
  '2': {
    func: (a, b) => a - b,
    aPrompt: 'Enter the value for A: ',
    bPrompt: 'Enter the value for B: ',
    resultText: 'The subtraction result is'
  },
  '3': {
    func: (a, b) => a * b,
    aPrompt: 'Enter the value for A: ',
    bPrompt: 'Enter the value for B: ',
    resultText: 'The multiplication result is'
  },
  '4': {
    func: (a, b) => a / b,
    aPrompt: 'Enter the value for A (dividend): ',
    bPrompt: 'Enter the value for B (divisor): ',
    resultText: 'The division result is'
  }
};

console.log('Choose the number for the operation you want to use.');
console.log('1 - Addition');
console.log('2 - Subtraction');
console.log('3 - Multiplication');
console.log('4 - Division');

const calcAB = prompt('Operation: ');

// 校验操作编号是否合法
if (operations[calcAB]) {
  const { func, aPrompt, bPrompt, resultText } = operations[calcAB];
  const a = Number(prompt(aPrompt));
  const b = Number(prompt(bPrompt));
  console.log(`${resultText} "${func(a, b)}"`);
} else {
  console.log('Invalid operation number!');
}

优点 #

• 所有操作的配置集中管理，后续新增运算只需在operations对象里添加新键值对，无需修改核心逻辑
• 彻底消除了重复的输入输出代码，代码结构更清晰

方案二：保留switch但精简重复逻辑 #

如果你想继续使用switch语句，可以把重复的输入输出逻辑抽离，switch仅负责赋值对应的运算函数和文本：

//Calculator of Basic Operations

// 用箭头函数简化运算函数定义
const addition = (a, b) => a + b;
const subtraction = (a, b) => a - b;
const multiplication = (a, b) => a * b;
const division = (a, b) => a / b;

console.log('Choose the number for the operation you want to use.');
console.log('1 - Addition');
console.log('2 - Subtraction');
console.log('3 - Multiplication');
console.log('4 - Division');

let calcAB = prompt('Operation: ');

// 声明变量存储当前操作的配置
let operationFunc, aPrompt, bPrompt, resultText;

switch (calcAB) {
  case '1':
    operationFunc = addition;
    aPrompt = 'Enter the value for A: ';
    bPrompt = 'Enter the value for B: ';
    resultText = 'The addition result is';
    break;
  case '2':
    operationFunc = subtraction;
    aPrompt = 'Enter the value for A: ';
    bPrompt = 'Enter the value for B: ';
    resultText = 'The subtraction result is';
    break;
  case '3':
    operationFunc = multiplication;
    aPrompt = 'Enter the value for A: ';
    bPrompt = 'Enter the value for B: ';
    resultText = 'The multiplication result is';
    break;
  case '4':
    operationFunc = division;
    aPrompt = 'Enter the value for A (dividend): ';
    bPrompt = 'Enter the value for B (divisor): ';
    resultText = 'The division result is';
    break;
  default:
    console.log('Invalid operation number!');
    // 浏览器环境下用return终止后续执行，Node环境用process.exit()
    return;
}

// 统一执行输入和输出逻辑
const a = Number(prompt(aPrompt));
const b = Number(prompt(bPrompt));
console.log(`${resultText} "${operationFunc(a, b)}"`);

优点 #

• 保留了你原本熟悉的switch结构，更容易理解和过渡
• 消除了每个case里重复的prompt和console.log代码

内容的提问来源于stack exchange，提问作者Duca Barros ヅカ 두카 牡羊埴