title: Element is not exported warning for JavaScript in WebStorm
body: <p>I don't understand why I am receiving the <code>element is not exported</code> in WebStorm IDE for the following JavaScript at the <code>this.errors</code> line. </p>
  
  <pre><code>function FooBar(userId, email) {
    if (!util.isString(userId) || !userId.length) {
      throw Error('FooBar(): requires a non-empty userId:String');
    }
  
    if (this instanceof FooBar) {
      this.id = generateId();
      this.userId = userId;
      this.email = email;
      this.curStep = WORKER_STEPS[0];
      this.completed = false;
      this.failed = false;
      this.createDate = new Date();
      this.errors = {};
      for (let step of WORKER_STEPS) {
        this.errors[step] = 0;
      }
    } else {
      return new FooBar(userId, email);
    }
  }
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/AFpj8.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/AFpj8.png" alt="enter image description here"></a></p>