typescript: Chain of Responsibility Pattern

 

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/**  * Chain of Responsibility Pattern 责任链是一种行为设计模式， 允许你将请求沿着处理者链进行发送， 直至其中一个处理者对其进行处理。  * file: Chaints.ts  * The Handler interface declares a method for building the chain of handlers.  * It also declares a method for executing a request.  */ interface Handler {     /**      *      * @param handler      */     setNext(handler: Handler): Handler;     /**      *      * @param request      */     handle(request: string): string; }   /**  * The default chaining behavior can be implemented inside a base handler class.  */ abstract class AbstractHandler implements Handler {     /**      *      */     private nextHandler: Handler;     /**      *      * @param handler      * @returns      */     public setNext(handler: Handler): Handler {         this.nextHandler = handler;         // Returning a handler from here will let us link handlers in a         // convenient way like this:         // monkey.setNext(squirrel).setNext(dog);         return handler;     }     /**      *      * @param request      * @returns      */     public handle(request: string): string {         if (this.nextHandler) {             return this.nextHandler.handle(request);         }           return null;     } }   /**  * All Concrete Handlers either handle a request or pass it to the next handler  * in the chain.  */ class MonkeyHandler extends AbstractHandler {     /**      *      * @param request      * @returns      */     public handle(request: string): string {         if (request === 'Banana') {             return `Monkey: I'll eat the ${request}.`;         }         return super.handle(request);       } }   /**  *  */ class SquirrelHandler extends AbstractHandler {     /**      *      * @param request      * @returns      */     public handle(request: string): string {         if (request === 'Nut') {             return `Squirrel: I'll eat the ${request}.`;         }         return super.handle(request);     } } /**  *  *  */ class DogHandler extends AbstractHandler {       /**      *      * @param request      * @returns      */     public handle(request: string): string {         if (request === 'MeatBall') {             return `Dog: I'll eat the ${request}.`;         }         return super.handle(request);     } }   /**  * The client code is usually suited to work with a single handler. In most  * cases, it is not even aware that the handler is part of a chain.  */ function clientCodeChain(handler: Handler) {       const foods = ['Nut', 'Banana', 'Cup of coffee'];     let str="";     for (const food of foods) {         console.log(`Client: Who wants a ${food}?`);           const result = handler.handle(food);         if (result) {             console.log(`  ${result}`);             str=str+","+result;         } else {             console.log(`  ${food} was left untouched.`);             str=str+","+food;         }     }     return str; }     let pubch1=""; let pubch2=""; let pubch3="Geovin Du"; let pubch4="geovindu"; /**  * The other part of the client code constructs the actual chain.  */ const monkey = new MonkeyHandler(); const squirrel = new SquirrelHandler(); const dog = new DogHandler();   monkey.setNext(squirrel).setNext(dog);   /**  * The client should be able to send a request to any handler, not just the  * first one in the chain.  */ console.log('Chain: Monkey > Squirrel > Dog\n'); pubch1=clientCodeChain(monkey); console.log('');   console.log('Subchain: Squirrel > Dog\n'); pubch2=clientCodeChain(squirrel);   let messageChain: string = 'Hello World,This is a typescript!,涂聚文 Geovin Du.Web'; document.body.innerHTML = messageChain+",<br/>one="+pubch1+",<br/>two="+pubch2+",<br/>three="+pubch3+",<br/>four="+pubch4+",<br/>TypeScript Chain of Responsibility Pattern 责任链模式";

　　

调用：

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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 Chain of Responsibility Pattern 责任链模式</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/Chaints.js"></script>     </body> </html>

　　

 

输出：

 tsconfig.json:

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{   "compilerOptions":    {      "target": "ES2015",     "module": "CommonJS",     "outDir": "./dist",     "rootDir": "./src",     "resolveJsonModule": true,     "composite": true,  // required on the dependency project for references to work https://github.com/microsoft/TypeScript/issues/30693     "sourceMap": true,     /*     "strict": true,     "experimentalDecorators": true,     "useDefineForClassFields": false,     "skipLibCheck": true,     "forceConsistentCasingInFileNames": true,     "esModuleInterop": true,     "moduleResolution": "node",       // Tells TypeScript to read JS files, as normally they are ignored as source files       "allowJs": true,       // Generate d.ts files       "declaration": true,       // go to js file when using IDE functions like "Go to Definition" in VSCode       "declarationMap": true,        // This compiler run should only output d.ts files       "emitDeclarationOnly": true*/       "baseUrl": ".",       "paths": {       "dotenv": ["./dist/du.d.ts"]     },     },   "includes": [   "src/**/*.ts",   "other-src/**/*.ts"   ],   "exclude":[     "rollup.config.js",     "test",     "dist",     "node_modules",   ], }