TS之函数及函数传参

//1 普通用法
function run(): string {
  return ‘run‘;
}

// function run1(): string {
//   return 111;  //报错
// }

//2 匿名函数方式
let fun1 = function (): number {
  return 123;
}
console.log(fun1());

function getInfo(uname: string, age: number): string {
  return `${uname}---${age}`;
}
console.log(getInfo(‘lisi‘, 12));

// 可选参数
function getInfo(uname: string, age?: number): string {
  if (age) {
    return `${uname}---${age}`;
  } else {
    return `${uname}---年龄保密`
  }
}
console.log(getInfo(‘lisi‘, 12));
console.log(getInfo(‘lisi‘));

function getInfo(uname: string, age: number = 20): string {
  if (age) {
    return `${uname}---${age}`;
  } else {
    return `${uname}---年龄保密`
  }
}
console.log(getInfo(‘lisi‘));
console.log(getInfo(‘lisi‘，30));

function sum(a: number, b: number, c: number, d: number): number {
  return a + b + c + d;
}
console.log(sum(1, 2, 3, 4));

function sum1(...res: number[]): number {
  return res.reduce((p, e, i, a) => {
    return p + e;
  }, 0)
}
console.log(sum1(1, 2, 3, 4, 5));

function getInfo(nam: string): string;
function getInfo(age: number): number;
function getInfo(str: any): any {
  if (typeof str === ‘string‘) {
    return `我叫：` + str;
  } else {
    return `年龄：` + str;
  }
};

console.log(getInfo(‘张三‘));
console.log(getInfo(25));
console.log(getInfo(错误));  //错误