add simple type checker implementation

js/src/util.js

@@ -23,6 +23,15 @@ const Util = (($) => {
     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,
@@ -115,6 +124,25 @@ const Util = (($) => {
 
     supportsTransitionEnd() {
       return !!transition
+    },
+
+    typeCheckConfig(componentName, config, configTypes) {
+
+      for (let property in configTypes) {
+        let expectedTypes = configTypes[property]
+        let value         = config[property]
+        let valueType
+
+        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}".`)
+        }
+      }
     }
 
   }