函数

1. 函数使用举例

function sum(num1: number, num2: number): number {
  return num1 + num2;
}
console.log(sum(2, 3));

// 函数表达式
const add = (num1: number, num2: number): number => {
  return num1 + num2;
};
const sub: (num1: number, num2: number) => number = (num1, num2) => {
  return num1 - num2;
};
console.log(add(1, 2));
console.log(sub(5, 2));

// 没有返回值的函数
function hello(name: string) {
  console.log(name);
}
hello("123");

// 可选参数 永远在必选参数后面
function mySli(must: number, start?: number, end?: number): void {
  console.log("start: ", start, "end: ", end);
}
mySli(0);
mySli(0, 1);
mySli(0, 1, 3);