面试题：TypeScript中ES6模块的基础导入导出

Question

请描述在TypeScript中如何使用ES6模块语法进行基本的导入和导出操作，分别给出默认导出、命名导出及其对应的导入方式的代码示例。

Answer 1

默认导出与导入

1. 默认导出示例

// mathUtils.ts
const add = (a: number, b: number): number => a + b;
export default add;

2. 默认导入示例

// main.ts
import add from './mathUtils';
const result = add(2, 3);
console.log(result); 

命名导出与导入

1. 命名导出示例

// geometry.ts
export const circleArea = (radius: number): number => Math.PI * radius * radius;
export const squareArea = (side: number): number => side * side;

2. 命名导入示例

// main.ts
import { circleArea, squareArea } from './geometry';
const circleResult = circleArea(5);
const squareResult = squareArea(4);
console.log(circleResult); 
console.log(squareResult); 

3. 命名导入时重命名示例

// main.ts
import { circleArea as ca, squareArea as sa } from './geometry';
const circleResult = ca(5);
const squareResult = sa(4);
console.log(circleResult); 
console.log(squareResult); 

4. 导入所有命名导出并使用一个对象接收示例

// main.ts
import * as geometry from './geometry';
const circleResult = geometry.circleArea(5);
const squareResult = geometry.squareArea(4);
console.log(circleResult); 
console.log(squareResult);