al tests passing, dist rebuilt, w/typechecker

dist/js/umd/util.js

@@ -37,6 +37,15 @@
       transition: 'transitionend'
     };
 
+    // shoutout AngusCroll (https://goo.gl/pxwQGp)
+    function toType(obj) {
+      return ({}).toString.call(obj).match(/\s([a-zA-Z]+)/)[1].toLowerCase();
+    }
+
+    function isElement(obj) {
+      return (obj[0] || obj).nodeType;
+    }
+
     function getSpecialTransitionEndEvent() {
       return {
         bindType: transition.end,
@@ -129,6 +138,21 @@
 
       supportsTransitionEnd: function supportsTransitionEnd() {
         return !!transition;
+      },
+
+      typeCheckConfig: function typeCheckConfig(componentName, config, configTypes) {
+
+        for (var property in configTypes) {
+          var expectedTypes = configTypes[property];
+          var value = config[property];
+          var valueType = undefined;
+
+          if (value && isElement(value)) valueType = 'element';else valueType = toType(value);
+
+          if (!new RegExp(expectedTypes).test(valueType)) {
+            throw new Error('' + componentName.toUpperCase() + ': ' + ('Option "' + property + '" provided type "' + valueType + '" ') + ('but expected type "' + expectedTypes + '".'));
+          }
+        }
       }
 
     };