Added TypeTraits reference.

Author: schlangster

reference/TypeTraits.h/index.md

@@ -5,4 +5,40 @@ groups:
  - {name: Home, url: ''}
  - {name: Reference , url: 'reference/'}
 ---
-Todo
+Contains traits for compile-time type inspection and transformation.
+
+## Header
+{% highlight C++ %}
+#include "react/Signal.h"
+{% endhighlight %}
+
+## Synopsis
+
+### Classes
+
+{% highlight C++ %}
+// True, if T is any signal type
+bool IsSignal<T>::value
+
+// True, if T is any event stream type
+bool IsEvent<T>::value
+
+// True, if T is any observer type
+bool IsObserver<T>::value
+
+// True, if T is any continuation type
+bool IsContinuation<T>::value
+
+// True, if T supports Observe()
+bool IsObservable<T>::value
+
+// True, if T is any reactive type,
+// including signals, event streams, observers and continutations
+bool IsReactive<T>::value
+
+// Decays VarSignal/EventSource to Signal/Events, respectively
+struct DecayInput<T>
+{ 
+    using Type = /* ... */
+}
+{% endhighlight %}