// 类继承
class Animal {
name: string
constructor(theName: string) { this.name = theName; }
move(distanceInMeters: number = 0) {
console.log(`${this.name} moved ${distanceInMeters}m.`)
}
}
class Snake extends Animal {
constructor(name: string) { super(name)} //调用父类构造器
move(distanceInMeters = 5) {
console.log("Slithering...")
super.move(distanceInMeters) //调用父类方法
}
}
class Horse extends Animal {
constructor(name: string) { super(name); }
move(distanceInMeters = 45) {
console.log("Galloping...");
super.move(distanceInMeters);
}
}
let sam = new Snake("Sammy the Python")
sam.move()
// Slithering...
// Sammy the Python moved 5m.
let tom :Animal = new Horse("Tommy the Palomino");
// 即使 tom被声明为 Animal类型,但因为它的值是 Horse,调用 tom.move(34)时,它会调用 Horse里重写的方法
tom.move(333)
// Galloping...
// Tommy the Palomino moved 333m.
// 类成员属性, 默认public
// 当成员被标记成 private时,它就不能在声明它的类的外部访问
class Person {
private name: string;
constructor(theName: string) { this.name = theName; }
}
class Student extends Person {
constructor() { super("Rhino"); }
}
const bob = new Student()
// bob.name error
// protected修饰符与 private修饰符的行为很相似,但有一点不同, protected成员在派生类中仍然可以访问
class Person2 {
protected name: string;
constructor(name: string) { this.name = name; }
}
class Employee extends Person2 {
private department: string;
constructor(name: string, department: string) {
super(name)
// this.name = '11111'
this.department = department;
}
public getElevatorPitch() {
return `Hello, my name is ${this.name} and I work in ${this.department}.`;
}
}
let howard = new Employee("Howard", "Sales");
console.log(howard.getElevatorPitch());
// console.log(howard.name); // 错误
// 参数属性
// 参数属性通过给构造函数参数前面添加一个访问限定符来声明。
// 使用 private限定一个参数属性会声明并初始化一个私有成员;对于 public和 protected来说也是一样。
class Octopus {
readonly numberOfLegs: number = 8;
constructor(private name: string) {
}
}
const nsjd = new Octopus('bob')
//const bobName = nsjd.name //error
//存储器
let passcode = "secret passcode2";
class Employee4 {
private _fullName: string;
get fullName(): string {
return this._fullName;
}
set fullName(newName: string) {
if (passcode && passcode == "secret passcode") {
this._fullName = newName;
}
else {
console.log("Error: Unauthorized update of employee!");
}
}
}
let employee = new Employee4();
employee.fullName = "Bob Smith"; // Error: Unauthorized update of employee!
if (employee.fullName) {
alert(employee.fullName);
}
// 类的静态属性
class Book{
constructor(public bookName:string){}
static getName(){
return `i am a static method`
}
}
const abc = new Book('Harry Port')
console.log(abc.bookName) //成员变量
console.log(Book.getName()) //静态方法
// 抽象类
// 抽象类做为其它派生类的基类使用。 它们一般不会直接被实例化。
// 抽象类中的抽象方法不包含具体实现并且必须在派生类中实现
abstract class Computer{
constructor(public type:string){}
printType():void{
console.log(this.type)
}
abstract printPrice(price:number):void // 抽象方法
}
class Mac extends Computer{
constructor(type:string){
super(type)
console.log('start constructor')
}
printPrice(price:number):void{ //实现抽象方法
console.log(`the ${this.type} computer's price is ${price}`)
}
getSoft():void{
console.log('hello wold')
}
}
const macpro = new Mac('MacBook Pro')
macpro.printType()
macpro.printPrice(13000)
macpro.getSoft()
class Greeter {
static standardGreeting = "Hello, there";
greeting: string;
greet() {
if (this.greeting) {
return "Hello, " + this.greeting;
}
else {
return Greeter.standardGreeting;
}
}
}
let greeter1: Greeter;
greeter1 = new Greeter();
console.log(greeter1.greet());
let greeterMaker: typeof Greeter = Greeter;
greeterMaker.standardGreeting = "Hey there!";
let greeter2: Greeter = new greeterMaker();
console.log(greeter2.greet());
TypeScript-类
©著作权归作者所有,转载或内容合作请联系作者
- 文/潘晓璐 我一进店门,熙熙楼的掌柜王于贵愁眉苦脸地迎上来,“玉大人,你说我怎么就摊上这事。” “怎么了?”我有些...
- 文/花漫 我一把揭开白布。 她就那样静静地躺着,像睡着了一般。 火红的嫁衣衬着肌肤如雪。 梳的纹丝不乱的头发上,一...
- 文/苍兰香墨 我猛地睁开眼,长吁一口气:“原来是场噩梦啊……” “哼!你这毒妇竟也来了?” 一声冷哼从身侧响起,我...
推荐阅读更多精彩内容
- TypeScript 类型兼容 Simple Private & Protected 编译不通过,Animal的n...
- 目前前端发展得百花齐放、技术日新月异,就连各种编辑器也好用到匪夷所思,又层出不穷。近两年来,我从Sublime T...