Add functions to objType utility

Author: eKoopmans

src/utils.js

@@ -1,12 +1,14 @@
 // Determine the type of a variable/object.
 export const objType = function(obj) {
-  if (typeof obj === 'undefined')                             return 'undefined';
-  else if (typeof obj === 'string' || obj instanceof String)  return 'string';
-  else if (typeof obj === 'number' || obj instanceof Number)  return 'number';
-  else if (!!obj && obj.constructor === Array)                return 'array';
-  else if (obj && obj.nodeType === 1)                         return 'element';
-  else if (typeof obj === 'object')                           return 'object';
-  else                                                        return 'unknown';
+  var type = typeof obj;
+  if (type === 'undefined')                                 return 'undefined';
+  else if (type === 'string' || obj instanceof String)      return 'string';
+  else if (type === 'number' || obj instanceof Number)      return 'number';
+  else if (type === 'function' || obj instanceof Function)  return 'function';
+  else if (!!obj && obj.constructor === Array)              return 'array';
+  else if (obj && obj.nodeType === 1)                       return 'element';
+  else if (type === 'object')                               return 'object';
+  else                                                      return 'unknown';
 };
 
 // Create an HTML element with optional className, innerHTML, and style.