getPaddingString(): string; } class SpaceRepeatingPadder implements Padder { constructor(private numSpaces: number) {} getPaddingString() { return Array(this.numSpaces + 1).join(" "); } } class StringPadder imp
The members of a class (properties & methods) are typed using type annotations, similar to variables. ExampleGet your own TypeScript Server classPerson { name: string; } constperson =newPerson(); person.name="Jane"; Try it Yourself » ...
getName() { return this.name } } let boy = new Boy() console.log(boy.getName()) // human 静态属性 属性前加上static关键字,就表示该属性不会被实例继承。 静态属性只能通过类来访问 class Animal { static num = 42; constructor() { // ... } } console.log(Animal.num); // 42 const ...
classApiClient{privatereadonly baseUrl="https://api.example.com/";// 推断类型: "https://api.example.com/"get(endpoint:string)
泛型接口(Generic Interfaces)可以使用泛型来定义接口,使接口的成员能够使用任意类型:实例// 基本语法interface Pair { first: T; second...Box("TypeScript");console.log(stringBox.getValue()); // 输出: TypeScript解析: 在这个例子中,Box 是一个泛型类,使用...,但有一个约束条件,即 T 必须实现 ...
/*** Represents a book in the catalog.* @public*/export class Book {/*** The title of the book.* @beta*/public get title(): string;/*** The author of the book.*/public get author(): string;}; 在这个例子中,Book.author从包含它的类继承了它的@public名称,而Book.title被标记为“...
Back when TypeScript first introduced index signatures, you could only get properties declared by them with “bracketed” element access syntax like person["name"]. Copy interface SomeType { /** This is an index signature. */ [propName: string]: any; } function doStuff(value: SomeType) {...
class SafeBox { #value: string | undefined; // Only accepts strings! set value(newValue: string) { } // Must check for 'undefined'! get value(): string | undefined { return this.#value; } } In fact, this is similar to how optional properties are checked under --exactOptionalProp...
Figure 1 A Simple Person ClassJavaScript Copy export class Person { firstName: string; lastName: string; constructor(fn: string, ln: string) { this.firstName = fn; this.lastName = ln; } greet() : string { return this.fullName + " says hello!"; } get fu...
classPoint{publicx:number=0publicy:number=0constructor(x:number, y:number){this.x = x;this.y = y; } }// 无法从对象中删除某个属性,从而确保所有Point对象都具有属性xletp1 =newPoint(1.0,1.0);deletep1.x;// 在TypeScript和ArkTS中,都会产生编译时错误delete(p1asany).x;// 在TypeScript中不...