如何改进TypeScript/Angular方法中的参数？

function greet(name?: string) {
  if (name) {
    console.log(`Hello, ${name}!`);
  } else {
    console.log("Hello, stranger!");
  }
}

greet(); // 输出：Hello, stranger!
greet("John"); // 输出：Hello, John!

function greet(name: string = "stranger") {
  console.log(`Hello, ${name}!`);
}

greet(); // 输出：Hello, stranger!
greet("John"); // 输出：Hello, John!

interface GreetOptions {
  name: string;
  age: number;
  language?: string;
}

function greet(options: GreetOptions) {
  console.log(`Hello, ${options.name}! You are ${options.age} years old.`);
  if (options.language) {
    console.log(`Your preferred language is ${options.language}.`);
  }
}

greet({ name: "John", age: 25 }); // 输出：Hello, John! You are 25 years old.
greet({ name: "Jane", age: 30, language: "English" }); // 输出：Hello, Jane! You are 30 years old. Your preferred language is English.

function processInput(input: string): string;
function processInput(input: number): number;
function processInput(input: string | number): string | number {
  if (typeof input === "string") {
    return input.toUpperCase();
  } else if (typeof input === "number") {
    return input * 2;
  }
}

console.log(processInput("hello")); // 输出：HELLO
console.log(processInput(5)); // 输出：10