title: Cannot find type definition file for 'core-js'
body: <p>I am building an <code>angular2</code> application with <code>angular-cli</code>. <code>angular-in-memory-web-api</code> was not installed by default.</p>
  
  <p>So I searched for it and added this line <code>"angular-in-memory-web-api": "~0.1.5"</code> in my <code>package.json</code> file. And did <code>npm install</code>.</p>
  
  <p>Now I am having this issue. </p>
  
  <pre><code>ERROR in [default] /home/adil/Code/AngularJS.2/cli-based/mz-doc-app/node_modules/angular-in-memory-web-api/in-memory-backend.service.d.ts:1:0 
  Cannot find type definition file for 'core-js'.
  </code></pre>
  
  <p>Please suggest some solution ?</p>
  
  <p><code>package.json</code></p>
  
  <pre><code>{
    "name": "mz-doc-app",
    "version": "0.0.0",
    "license": "MIT",
    "angular-cli": {},
    "scripts": {
      "start": "ng serve",
      "lint": "tslint \"src/**/*.ts\"",
      "test": "ng test",
      "pree2e": "webdriver-manager update",
      "e2e": "protractor"
    },
    "private": true,
    "dependencies": {
      "@angular/common": "~2.1.0",
      "@angular/compiler": "~2.1.0",
      "@angular/core": "~2.1.0",
      "@angular/forms": "~2.1.0",
      "@angular/http": "~2.1.0",
      "@angular/material": "^2.0.0-alpha.9-3",
      "@angular/platform-browser": "~2.1.0",
      "@angular/platform-browser-dynamic": "~2.1.0",
      "@angular/router": "~3.1.0",
      "@types/core-js": "^0.9.34",
      "angular-in-memory-web-api": "~0.1.5",
      "core-js": "^2.4.1",
      "rxjs": "5.0.0-beta.12",
      "ts-helpers": "^1.1.1",
      "zone.js": "^0.6.23"
    },
    "devDependencies": {
      "@types/jasmine": "^2.2.30",
      "@types/node": "^6.0.42",
      "angular-cli": "1.0.0-beta.18",
      "codelyzer": "1.0.0-beta.1",
      "jasmine-core": "2.4.1",
      "jasmine-spec-reporter": "2.5.0",
      "karma": "1.2.0",
      "karma-chrome-launcher": "^2.0.0",
      "karma-cli": "^1.0.1",
      "karma-jasmine": "^1.0.2",
      "karma-remap-istanbul": "^0.2.1",
      "protractor": "4.0.9",
      "ts-node": "1.2.1",
      "tslint": "3.13.0",
      "typescript": "~2.0.3"
    }
  }
  </code></pre>