js+文件+export

// mathFunctions.js
const add = (x, y) => x + y;
const subtract = (x, y) => x - y;

export default {
  add,
  subtract
};

// utils.js
export const greet = (name) => `Hello, ${name}!`;
export const farewell = (name) => `Goodbye, ${name}!`;

// app.js
import math from './mathFunctions.js';
import { greet, farewell } from './utils.js';

console.log(math.add(1, 2)); // 输出: 3
console.log(math.subtract(3, 1)); // 输出: 2
console.log(greet('Alice')); // 输出: Hello, Alice!
console.log(farewell('Bob')); // 输出: Goodbye, Bob!

// 错误的导入方式
import math from './mathFunctions'; // 缺少文件扩展名

// 正确的导入方式
import math from './mathFunctions.js';