ts的class类

声明一个类

class Point {
  public x: number
  public y: number
  constructor(x: number,y: number) {
    this.x = x;
    this.y = y;
  }
  public getPosition () {
    return `(${this.x},${this.y})`
  }
}
const point = new Point(1,2);
console.log(point);

修饰符

• public
  公共的，可以被实例和子类继承 ，子类中使用 super.属性 会报错，只能拿到 super.方法，属性只能用this.属性
• private
  私有的，不可以被实例和子类继承,只能在类中用this进行访问

class Parent {
  private age: number;
  constructor(age: number) {
    this.age = age;
  }
}

const p = new Parent(18);
console.log(p.age) // 报错：Property 'age' is private and only accessible within class 'Parent'.

• protected
  受保护的，可被子类继承，不可被实例继承，子类中使用 super.属性 会报错，只能拿到 super.方法,属性只能用this.属性
• readonly
  只读的，只能读取不能修改

class Parent {
 public readonly name: string;
 constructor(name: string) {
   this.name = name;
 }
}


const p = new Parent("tom");
p.name = "li"; // 报错： Cannot assign to 'name' because it is a read-only property.

get、set

class Parent {
  public age: number
  private _name: string | undefined;
  constructor(age: number) {
    this.age = age;
  }
  get name(){
    return this._name;
  }
  set name(value){
    this._name = value;
  }
}

const p = new Parent(18);
p.name = "123";
console.log(p.name)