Delete js files from dist folder when deleting ts files angular 2 project

Question

I followed the answer here

Separate Angular2 TypeScript files and JavaScript files into different folders, maybe 'dist‘ in order to separate my files into app and dist folders. The interesting thing is that when I create a new .ts file somewhere in the app folder ir creates a .js and .js.map files automatically in the dist folder, but when I delete a .ts file from the app folder the corresponfing .js and .js.map files from the dist folder are not deleted. Why is that and how can I fix it ?

package.json

{
  "name": "angular-quickstart",
  "version": "1.0.0",
  "scripts": {
    "start": "concurrently \"npm run tsc:w\" \"npm run lite\" ",
    "lite": "lite-server",
    "tsc": "tsc",
    "tsc:w": "tsc -w"
  },
  "licenses": [
    {
      "type": "MIT",
      "url": "https://github.com/angular/angular.io/blob/master/LICENSE"
    }
  ],
  "dependencies": {
    "@angular/common": "2.3.0",
    "@angular/compiler": "2.3.0",
    "@angular/core": "2.3.0",
    "@angular/forms": "2.3.0",
    "@angular/http": "2.3.0",
    "@angular/platform-browser": "2.3.0",
    "@angular/platform-browser-dynamic": "2.3.0",
    "@angular/router": "3.3.0",
    "@angular/upgrade": "2.3.0",
    "angular-in-memory-web-api": "0.2.0",
    "core-js": "2.4.1",
    "primeng": "1.0.0",
    "querystring": "0.2.0",
    "reflect-metadata": "0.1.8",
    "rxjs": "5.0.0-rc.4",
    "systemjs": "0.19.39",
    "zone.js": "0.7.2"
  },
  "devDependencies": {
    "@types/core-js": "0.9.34",
    "@types/node": "6.0.45",
    "concurrently": "3.0.0",
    "lite-server": "2.2.2",
    "typescript": "2.1.4"
  }
}

tsconfig.json

{
  "compilerOptions": {
    "target": "ES5",
    "module": "commonjs",
    "moduleResolution": "node",
    "sourceMap": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "removeComments": false,
    "noImplicitAny": false,
    "inlineSourceMap": false,
    "inlineSources": false,
    "outDir" : "dist"
  },
   "exclude": [
    "node_modules",
    "typings/main",
    "typings/main.d.ts"
  ],
  "compileOnSave": true
}

systemjs.config.js

/**
 * System configuration for Angular samples
 * Adjust as necessary for your application needs.
 */
(function (global) {
  System.config({
    paths: {
      // paths serve as alias
      'npm:': 'node_modules/'
    },
    // map tells the System loader where to look for things
    map: {
      // our app is within the app folder
      app: 'dist',
      // our app modules
      'domain' : 'app/domain',
      // angular bundles
      '@angular/core': 'npm:@angular/core/bundles/core.umd.js',
      '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
      '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
      '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
      '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
      '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
      '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
      '@angular/router/upgrade': 'npm:@angular/router/bundles/router-upgrade.umd.js',
      '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',
      '@angular/upgrade': 'npm:@angular/upgrade/bundles/upgrade.umd.js',
      '@angular/upgrade/static': 'npm:@angular/upgrade/bundles/upgrade-static.umd.js',
      // other libraries
      'rxjs':                      'npm:rxjs',
      'angular-in-memory-web-api': 'npm:angular-in-memory-web-api/bundles/in-memory-web-api.umd.js',
      'primeng':                   'npm:primeng'            
    },
    // packages tells the System loader how to load when no filename and/or no extension
    packages: {
      app: {
        main: './main.js',
        defaultExtension: 'js'                
      },
      // for our app modules
      domain : {
        main: 'index.js',  defaultExtension: 'js'
      },
      // other libraries
      rxjs: {
        defaultExtension: 'js'
      },
      primeng: {
          defaultExtension: 'js'
      }      
    }
  });
})(this);