title: how to pass parameters to Handlebars helper? What's the difference between options.hash & options.data
body: <p>Here's a typical Handlebars helper:</p>
  
  <pre><code>Ember.Handlebars.helper 'myHelper', (value, options) -&gt;
    ...
  </code></pre>
  
  <p>According to <a href="https://coderwall.com/p/bs67zw" rel="noreferrer">this protip</a> you can pass hash to Handlebars helpers. I looked over the source and found out that it provides both <code>options.hash</code> and <code>options.data</code>. I'm a bit confused as this wouldn't work as expected:</p>
  
  <pre><code>{{#with controllers.currentCardCategory}}
    {{#each property in cardProperties}}
      &lt;td class="td"&gt;{{cardProperty this property=property.symbol}}&lt;/td&gt; 
    {{/each}}
  {{/with}}
  </code></pre>
  
  <p><code>this</code> is the current <code>Card</code> record. Here I got <code>property.symbol</code> as string</p>
  
  <p>But this worked:</p>
  
  <pre><code>{{#with controllers.currentCardCategory}}
    {{#each property in cardProperties}}
      &lt;td class="td"&gt;{{cardProperty this property.symbol}}&lt;/td&gt; 
    {{/each}}
  {{/with}}
  </code></pre>
  
  <p>and the value was accessible via <code>options</code>.</p>
  
  <p>But now I can't do this:</p>
  
  <pre><code>{{#with controllers.currentCardCategory}}
    {{#each property in cardProperties}}
      &lt;td class="td"&gt;{{cardProperty this property.symbol anotherParam yetAnotherParam}}&lt;/td&gt; 
    {{/each}}
  {{/with}}
  </code></pre>
  
  <p>My question is: <strong>how to pass other parameters to the helper</strong> and <strong>what's the difference between <code>options.hash</code> and <code>options.data</code> in the helper</strong>?</p>