TypeScript 箭头函数

// 1. 基础语法
// 普通函数
function add(a: number, b: number): number {return a + b;
}// 转换为箭头函数
const addArrow = (a: number, b: number): number => {return a + b;
};// 2. 单行返回值省略大括号和 return
const multiply = (a: number, b: number): number => a * b;// 3. 单个参数省略括号
const square = (x: number): number => x * x;
// 更简洁写法
const squareSimple = x => x * x;// 4. 无参数需要括号
const getRandom = (): number => Math.random();// 5. 箭头函数与 this 绑定
class Counter {count: number = 0;// 使用箭头函数确保 this 指向实例increment = () => {this.count++;};
}// 6. 泛型箭头函数
const identity = <T>(arg: T): T => arg;// 7. 异步箭头函数
const fetchData = async (url: string): Promise<string> => {const response = await fetch(url);return response.text();
};