title: IE11 Angular-CLI source maps not working
body: <p><a href="https://i.stack.imgur.com/N64FG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/N64FG.png" alt="Source maps are showing up in the JavaScript bundle"></a></p>
  
  <p>Using Angular-CLI 1.0 and Angular 4, I am unable to get source maps working despite having <code>//# sourceMappingURL=main.bundle.js.map</code> in the bundled JavaScript.  Does anyone know a work around to get the sourcemaps working in IE-11?  Normally this wouldn't be a huge issue, I'd just switch to firefox or chrome. But I'm developing an Excel add-in with the Office-js api, and it uses an embedded IE11 browser to display the add-in, so I'm stuck with it.</p>
  
  <p>My tsconfig.json: </p>
  
  <pre><code>{
    "compileOnSave": false,
    "compilerOptions": {
      "outDir": "./dist/out-tsc",
      "baseUrl": "src",
      "sourceMap": true,
      "declaration": false,
      "moduleResolution": "node",
      "emitDecoratorMetadata": true,
      "experimentalDecorators": true,
      "pretty": true,
      "target": "es5",
      "typeRoots": [
        "node_modules/@types"
      ],
      "lib": [
          "es2017",
          "dom"
      ]
    }
  }
  </code></pre>
  
  <p>tsconfig.app.json:</p>
  
  <pre><code>{
    "extends": "../tsconfig.json",
    "compilerOptions": {
      "outDir": "../out-tsc/app",
      "module": "es2015",
      "baseUrl": "",
      "types": []
    },
    "exclude": [
      "test.ts",
      "**/*.spec.ts"
    ]
  }
  </code></pre>