基础类型

let str: string = "Hello, TypeScript";
let num: number = 42;
let bool: boolean = true;

定义一个接口

interface Person {
  name: string;
  age: number;
}

function greet(person: Person): string {
  return `Hello, ${person.name}! You are ${person.age} years old.`;
}

let user: Person = { name: "John", age: 25 };
let greeting: string = greet(user);

定义一个类

class Animal {
  constructor(public name: string) {}

  makeSound(): string {
    return "Some generic sound";
  }
}

class Dog extends Animal {
  makeSound(): string {
    return "Woof, woof!";
  }
}

let myDog: Dog = new Dog("Buddy");
let sound: string = myDog.makeSound();

简单介绍下接口和类的区别

接口不包含方法的实例化，类包含

下面用简单的例子来表示

// 接口示例
interface Shape {
  area(): number;
}

// 类示例
class Circle implements Shape {
  constructor(private radius: number) {}

  area(): number {
    return Math.PI * this.radius ** 2;
  }
}

const circleInstance = new Circle(5);
console.log(circleInstance.area()); // 输出: 78.54

接口继承与类实现

interface Shape {
  draw(): void;
}

class Circle implements Shape {
  draw(): void {
    console.log("Drawing a circle");
  }
}

异步编程

function fetchData(): Promise<string> {
  return new Promise((resolve) => {
    setTimeout(() => {
      resolve("Data fetched successfully");
    }, 2000);
  });
}

async function fetchDataAsync(): Promise<void> {
  let data: string = await fetchData();
  console.log(data);
}