title: Handlebars conditional checked property from Jade template
body: <p>I'd like my handlebars template that's served to the client to look like </p>
  
  <pre><code>&lt;input type='checkbox' checked={{isChecked}}&gt;
  </code></pre>
  
  <p>or</p>
  
  <pre><code>&lt;input type='checkbox' {{#if isChecked}}checked{{/if}}&gt;
  </code></pre>
  
  <p>How can I write a Jade template that will compile to this? from their docs, the checked property will be included if the assigned value is truthy but not actually include the value:</p>
  
  <pre><code>input(type="checkbox", checked="{{isChecked}}")
  </code></pre>
  
  <p>compiles to </p>
  
  <pre><code>&lt;input type='checkbox' checked&gt;
  </code></pre>
  
  <p>I've also tried:</p>
  
  <pre><code>input(type="checkbox", checked={{isChecked}})
  </code></pre>
  
  <p>and</p>
  
  <pre><code>input(type="checkbox", {{#if isChecked}}checked{{/if}})
  </code></pre>
  
  <p>that just fails to compile, which I understand</p>