Why apply() here takes only one argument instead of two?
<p>I'm reading the book Javascript: The Good Parts. And I'm confused by the following code.</p>

<pre><code>Function.method('curry', function (  ) {
    var slice = Array.prototype.slice,
        args = slice.apply(arguments),
        that = this;
    return function (  ) {
        return that.apply(null, args.concat(slice.apply(arguments)));
    };
});
</code></pre>

<p>Where is the <code>null</code> in <code>slice.apply(arguments)</code>?</p>
