title: Safari, TypeScript, Angular2: const keyword are not supported in strict mode
body: <p>I develop a web site using Angular2 + TypeScript.
  When I use Google Chrome, my application is properly working.
  But, when I use Safari, it displays the following message and my application doesn't work.</p>
  
  <pre><code>const keyword are not supported in strict mode
  </code></pre>
  
  <p>My tsconfig.json is:</p>
  
  <pre><code>{
    "compilerOptions": {
      "outDir": "public/js",
      "module": "system",
      "target": "es5",
      "noImplicitAny": false,
      "removeComments": false,
      "sourceMap": false,
      "moduleResolution": "node",
      "experimentalDecorators": true,
      "emitDecoratorMetadata": true
    },
    "exclude": [
      "node_modules"
    ],
    "files": [
      "./src/ts/main.ts"
    ]
  }
  </code></pre>
  
  <p>There is full source code in <a href="https://github.com/c-bata/c-bata.github.io" rel="noreferrer">my github repository</a>.</p>