title: Why IDBKeyRange.only() does not allow boolean?
body: <p>I have an index in my object store, created like this:</p>
  
  <pre><code>objStore.createIndex("pinned", "pinned");
  </code></pre>
  
  <p>I want to store values of boolean type there. And unfortunately I can't get only records with "pinned" field set to "true". Why does this happen? Is this my database design mistake?</p>
  
  <pre><code>IDBKeyRange.only(true)
  Firefox: [Exception... "Data provided to an operation does not meet requirements."  code: "0" nsresult: "0x80660005 (DataError)"  location: "Web Console Line: 1"]
  </code></pre>