TypeScript: Factory Method pattern

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npm install -g typescript
npm install -g ts-node

index.ts

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//import * as fs from "fs";   //TypeScript 工厂方法模式  Factory Method in TypeScript /**  * The Creator class declares the factory method that is supposed to return an  * object of a Product class. The Creator's subclasses usually provide the  * implementation of this method.  */ abstract class Creator {     /**      * Note that the Creator may also provide some default implementation of the      * factory method.      */     public abstract factoryMethod(): Product;       /**      * Also note that, despite its name, the Creator's primary responsibility is      * not creating products. Usually, it contains some core business logic that      * relies on Product objects, returned by the factory method. Subclasses can      * indirectly change that business logic by overriding the factory method      * and returning a different type of product from it.      */     public someOperation(): string {         // Call the factory method to create a Product object.         const product = this.factoryMethod();         // Now, use the product.         return `Creator: The same creator's code has just worked with ${product.operation()}`;     } }   /**  * Concrete Creators override the factory method in order to change the  * resulting product's type.  */ class ConcreteCreator1 extends Creator {     /**      * Note that the signature of the method still uses the abstract product      * type, even though the concrete product is actually returned from the      * method. This way the Creator can stay independent of concrete product      * classes.      */     public factoryMethod(): Product {         return new ConcreteProduct1();     } }   class ConcreteCreator2 extends Creator {     public factoryMethod(): Product {         return new ConcreteProduct2();     } }   /**  * The Product interface declares the operations that all concrete products must  * implement.  */ interface Product {     operation(): string; }   /**  * Concrete Products provide various implementations of the Product interface.  */ class ConcreteProduct1 implements Product {     public operation(): string {         return '{Result of the ConcreteProduct1 涂聚文}';     } } /**  * 返回字符串  */ class ConcreteProduct2 implements Product {     public operation(): string {         return '{Result of the ConcreteProduct2 Geovin Du}';     } }   /**  * The client code works with an instance of a concrete creator, albeit through  * its base interface. As long as the client keeps working with the creator via  * the base interface, you can pass it any creator's subclass.  */ function clientCode(creator: Creator) {     // ...     console.log('Client: I\'m not aware of the creator\'s class, but it still works.');     console.log(creator.someOperation());     // ... }         const hello : string = "Hello World,This is a typescript!,涂聚文，hi." console.log(hello)   console.log('App: Launched with the ConcreteCreator1.'); let cr1=new ConcreteCreator1(); clientCode(cr1); let pu1:string =cr1.someOperation(); console.log('');   console.log('App: Launched with the ConcreteCreator2.'); let cr2=new ConcreteCreator2(); clientCode(cr2); let pu2:string=cr2.someOperation(); console.log("geovindu");     let message: string = 'Hello World,This is a typescript!,涂聚文 Web'; document.body.innerHTML = message+","+pu1+","+pu2+",TypeScript 工厂方法模式"; /* const path = "./src/message.txt"; const data = "Hello World!"; const encoding = "utf8";   console.log(data);   fs.writeFile(path, data, encoding, error => {     if (error) {         console.log(error);     } }); */   //https://code.visualstudio.com/docs/typescript/typescript-debugging

 

输出：

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<!doctype html> <html lang="en"> <head>   <meta charset="UTF-8">   <meta name="viewport"         content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">   <meta http-equiv="X-UA-Compatible" content="ie=edge">     <head><title>TypeScript Hello Web</title>       <meta name="Description" content="geovindu,涂聚文,Geovin Du"/>       <meta name="Keywords" content="geovindu,涂聚文,Geovin Du"/>       <meta name="author" content="geovindu,涂聚文,Geovin Du"/>       </head>     <body>         <script src="dist/index.js"></script>     </body> </html>