What is the purpose of "self.each(callback, array)" in the jQuery source code?
<p>jQuery's <code>.each</code> function takes exactly one argument- a function. And yet, In this piece of jQuery code, we see the following:</p>

<pre><code>if ( callback ) {
    self.each( callback, [ responseText, status, jqXHR ] );
}
</code></pre>

<p>Two args are being passed to <code>.each</code>. I'm assuming the values in brackets are params to the callback function, but I'm not clear on why this is possible and why someone would do this rather than calling the function directly? :</p>

<pre><code>if ( callback ) {
    self.each( callback(responseText, status, jqXHR) );
}
</code></pre>
