pre><code class="lang-javascript">var pending = stream()
</code></pre>
<p>If a stream is dependent on more than one stream, any of its parent streams is in a pending state, the dependent streams is also in a pending state, and does not update its value.</p>
<pre><code class="lang-javascript">var a = stream(5)
var b = stream() // pending stream

var added = stream.combine(function(a, b) {
    return a() + b()
}, [a, b])

console.log(added()) // logs undefined
</code></pre>
<p>In the example above, <code>adde