title: @angular/common error TS2304 cannot find name 'unknown'
body: <p>I am trying to build an old project but unable to do it because of below errors.Using angular 5.2.9 to build the project but getting these errors.Can someone help</p>
  
  <p>My package.json file looks like this</p>
  
  <pre><code>"dependencies": {
   "@angular/core": "&gt;=5.2.9",
   "@angular/router": "&gt;=5.2.9",
   "ng-packagr": "^3.0.6",
   "rxjs-compat": "^6.2.2"
   },
  
    "devDependencies": {
      "@angular/common": "&gt;=5.2.9",
      "@angular/compiler": "&gt;=5.2.9",
      "@angular/compiler-cli": "^6.1.0",
      "@angular/platform-browser": "&gt;=5.2.9",
      "@angular/platform-browser-dynamic": "&gt;=5.2.9",
      "@angular/platform-server": "&gt;=5.2.9",
      "@types/es6-shim": "^0.31.32",
      "@types/jasmine": "^2.5.40",
      "@types/selenium-webdriver": "^2.53.39",
      "awesome-typescript-loader": "^3.1.2",
      "extract-text-webpack-plugin": "^2.1.0",
      "jasmine-core": "^2.5.2",
      "rxjs": "^6.5.2",
      "source-map-loader": "^0.2.0",
      "ts-helpers": "^1.1.2",
      "tslint": "^4.5.1",
      "tslint-loader": "^3.4.3",
      "typescript": "^2.2.1",
      "webpack": "2.1.0-beta.22",
      "webpack-dev-middleware": "^1.10.1",
      "webpack-dev-server": "^2.4.1",
      "webpack-md5-hash": "0.0.5",
      "webpack-merge": "^4.0.0",
      "zone.js": "&gt;=0.7.2"
    },
  </code></pre>
  
  <p>Build is happening but I am getting these warnings when running test cases</p>
  
  <pre><code>WARNING in ./~/rxjs-compat/observable/merge.js
  Cannot find source file '../src/compat/observable/merge.ts': Error: Can't resolve '../src/compat/observable/merge.ts' in 'D:\MASTERS\master-sales\node_modules\rxjs-compat\observable'
   @ ./~/rxjs/observable/merge.js 6:9-48
   @ ./~/@angular/core/esm5/core.js
   @ ./src/master-sales.service.ts
   @ ./src/master-sales.service.spec.ts
   @ ./src \.spec\.ts
   @ ./spec-bundle.js
  
  WARNING in ./~/rxjs-compat/add/observable/from.js
  Cannot find source file '../../src/compat/add/observable/from.ts': Error: Can't resolve '../../src/compat/add/observable/from.ts' in 'D:\MASTERS\master-sales\node_modules\rxjs-compat\add\observable'
   @ ./~/rxjs-compat/Rx.js 24:0-32
   @ ./~/rxjs/Rx.js
   @ ./spec-bundle.js
  
  WARNING in ./~/rxjs-compat/add/observable/fromEvent.js
  Cannot find source file '../../src/compat/add/observable/fromEvent.ts': Error: Can't resolve '../../src/compat/add/observable/fromEvent.ts' in 'D:\MASTERS\master-sales\node_modules\rxjs-compat\add\observable'
   @ ./~/rxjs-compat/Rx.js 25:0-37
   @ ./~/rxjs/Rx.js
   @ ./spec-bundle.js
  WARNING in ./~/rxjs-compat/add/observable/defer.js
  Cannot find source file '../../src/compat/add/observable/defer.ts': Error: Can't resolve '../../src/compat/add/observable/defer.ts' in 'D:\MASTERS\master-sales\node_modules\rxjs-compat\add\observable'
   @ ./~/rxjs-compat/Rx.js 21:0-33
   @ ./~/rxjs/Rx.js
   @ ./spec-bundle.js
  </code></pre>