• 实现 - 实现接口
• 泛化 - 继承父类
• 关联 - A 是 B 的属性

  实现

  
  实现一定要使用虚线和空心箭头 ```typescript interface IPerson { name: string age: number other: string sayHi(otherName: string): void }

class Person implements IPerson { name: string age: number constructor(name: string, age: number) { this.name = name this.age = age } sayHi(otherName: string) { console.log(hi, ${otherName}) } speak() {} eat() {} }

除了实现接口，还可以扩展一些方法，例如上诉栗子中，扩展了 other 属性，speak、eat 方法
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# 泛化（继承）
![](https://cdn.nlark.com/yuque/0/2022/jpeg/1670861/1656094937498-b2c204ec-bf3c-49c9-99e5-4c2992367bc8.jpeg)<br />实线，空心箭头
```typescript
class Person {
  name: string
  age: number
  protected weight: number = 100
  private girlFriend: string = 'xxx'
  constructor(name: string, age: number) {
    this.name = name
    this.age = age
  }
  eat(){}
  speak() {}
}
class Student extends Person {
  school: string
  constructor(name: string, age: number, school: string) {
    super(name, age)
    this.school = school
  }
  study() {}
  eat() {}
}
class Teacher extends Person {
  major: string
  teach() {}
}

关联

class Employee {
  name: string
  timeCard: TimeCard
  constructor(name: string, timeCard: TimeCard) {
    this.name = name
    this.timeCard = timeCard
  }
}

class TimeCard {}