Added: class combiner code

src/utils/combineCssClasses.js

@@ -0,0 +1,15 @@
+export const combineClasses = (...classes) => {
+  return classes.reduce((classNames, currentClassName) => {
+    if (Array.isArray(currentClassName)) {
+      return currentClassName[0] ? classNames + ' ' + currentClassName[1] : classNames;
+    } else if (currentClassName) {
+      return classNames + ' ' + currentClassName;
+    } else {
+      return classNames;
+    }
+  }, '');
+};
+
+export default combineClasses;
+
+// Ref: https://www.npmjs.com/package/combine-classes