Added a few type checking snippets from lodash

snippets/isRegExp.md

@@ -0,0 +1,13 @@
+### isRegExp
+
+Checks if value is classified as a RegExp object.
+
+Use the `instanceof`operator to check if the provided value is a `RegExp` object.
+
+```js
+const isRegExp = val => val instanceof RegExp;
+```
+
+```js
+isRegExp(/./g); // true
+```