title: ExperimentalDecorators Warning
body: <p>I had an application with Angular 4, and I tried test with jasmine and Karma. But this error it occurred.</p>
  
  <p>Experimental support for decorators is a feature that is subject to change in a
   future release. Set the 'experimentalDecorators' option to remove this warning.</p>
  
  <p>this  is my tsconfig file</p>
  
  <pre><code>{
    "compileOnSave": false,
    "compilerOptions": {
      "outDir": "./dist/",
      "baseUrl": "./",
      "sourceMap": true,
      "declaration": true,
      "module": "commonjs",
      "moduleResolution": "node",
      "emitDecoratorMetadata": true,
      "experimentalDecorators": true,
      "target": "es5",
      "typeRoots": [
        "node_modules/@types"
      ],
      "lib": [
        "es6",
        "dom"
      ]
    },
    "angularCompilerOptions": {
      "genDir": "aot",
      "strictMetadataEmit": true
    }
  }
  </code></pre>
  
  <p>I just edited settings.json of VScode and put this code</p>
  
  <pre><code>"typescript.tsdk": "node_modules\\typescript\\lib"
  </code></pre>
  
  <p>but didn't work. </p>