类
最后更新于：2022-04-02 03:28:06
[TOC]
##继承
```
class demo{
constructor(public name:string){
}
}
class foo extends demo{
getname():string{
return this.name
}
}
```
## 调用父类的方法
```
class demo{
constructor(public name:string){
}
getname(){
console.log(`parent ${this.name}`)
}
}
class foo extends demo{
constructor(name:string){
//调用父类的构造函数
super(" change "+name)
}
getname(){
//调用父类的同名方法
super.getname()
}
}
```
## readonly修饰符
```
class demo{
readonly age:number=23
constructor(public readonly name:string){
}
setname(name:string){
this.name=name; // 不能重新赋值
}
setage(age:number){
this.age=age //不能重新赋值
}
}
```
## 存取器
`getter/setters`
注意属性名`_name` 和get/set的方法名不可相同`name()`
```
class demo{
private _name:string
get name():string{
return `by get ${this._name}`
}
set name(name:string){
this._name=name
}
}
var d = new demo()
d.name="asd"
d.name;//by get asd
```
## 静态
```
class demo{
static name:string="123"
static getname(){
return "this is static as";
}
}
demo.name;
demo.getname();
```
## 抽象类
声明`abstract `关键字的需在子类中具体实现
```
abstract class demo{
abstract name:string; //需在子类中具体实现
age:number;
abstract getname(name:string):string;
setname():string{;
return "this is a setname";
}
}
class d extends demo{
name: string;
getname(name:string): string {
return this.name=name
}
}
```
## 把类当做接口使用
```
class Point {
x: number;
y: number;
}
interface Point3d extends Point {
z: number;
}
let point3d: Point3d = {x: 1, y: 2, z: 3};
```
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