Function for `fq` field of SOLR in SOLR-node-client
<p>For various fields such as <code>q</code> , <code>start</code> , <code>row</code> etc in SOLR we have corresponding functions in <a href="http://lbdremy.github.io/solr-node-client/" rel="nofollow">SOLR-node-client</a>.</p>

<p>So if I want to construct a query for the following:</p>

<pre><code>http://host:port/solr/eposro/select?q=cats.0%3A1&amp;start=0&amp;rows=4&amp;wt=json&amp;indent=true
</code></pre>

<p>I can use something like this:</p>

<pre><code>var query = client.createQuery()
                .q({cats.0 : 1})
                .start(0)
                .rows(4);
</code></pre>

<p>However, there is a filter query field in SOLR, <code>fq</code>. I don't seem to find a corresponding function for this in SOLR-node-client.</p>

<p>Following gives me error:</p>

<pre><code>var query = client.createQuery()
                .q({cats.0 : 1})
                .fq({'brand':'real'})
                .start(0)
                .rows(4);
</code></pre>

<p>I get an error saying that <code>fq</code> function doesn't exist.</p>

<p>Am I doing anything wrong or is there any other way to achieve filter query using SOLR-node-client?</p>