title: proper way of using es6 classes in a nodejs project
body: <p>I'd like to be able to use the cool es6 classes feature of nodejs 4.1.2</p>
  
  <p>I created the following project:</p>
  
  <p>a.js:</p>
  
  <pre><code>class a {
    constructor(test) {
     a.test=test;
    }
  }
  </code></pre>
  
  <p>index.js:</p>
  
  <pre><code>require('./a.js');
  var b = new a(5);
  </code></pre>
  
  <p>as you can see I create a simple class that it's constructor gets a parameter. and in my include i require that class and create a new object based on that class. pretty simple.. but still i'm getting the following error:</p>
  
  <pre><code>SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode
  at exports.runInThisContext (vm.js:53:16)
  at Module._compile (module.js:413:25)
  at Object.Module._extensions..js (module.js:452:10)
  at Module.load (module.js:355:32)
  at Function.Module._load (module.js:310:12)
  at Module.require (module.js:365:17)
  at require (module.js:384:17)
  at Object.&lt;anonymous&gt; (/Users/ufk/work-projects/bingo/server/bingo-tiny/index.js:1:63)
  at Module._compile (module.js:434:26)
  at Object.Module._extensions..js (module.js:452:10)
  </code></pre>
  
  <p>any ideas why ?</p>