diff --git a/lib/6to5/types/index.js b/lib/6to5/types/index.js
index b0ccb76d46..652e531cbf 100644
--- a/lib/6to5/types/index.js
+++ b/lib/6to5/types/index.js
@@ -13,10 +13,6 @@ var isString         = require("lodash/lang/isString");
 
 var t = exports;
 
-t.NATIVE_TYPE_NAMES = ["Array", "Object", "Number", "Boolean", "Date", "Array", "String"];
-
-//
-
 /**
  * Registers `is[Type]` and `assert[Type]` generated functions for a given `type`.
  * Pass `skipAliasCheck` to force it to directly compare `node.type` with `type`.
@@ -39,8 +35,7 @@ function registerType(type, skipAliasCheck) {
 }
 
 t.STATEMENT_OR_BLOCK_KEYS = ["consequent", "body"];
-
-//
+t.NATIVE_TYPE_NAMES = ["Array", "Object", "Number", "Boolean", "Date", "Array", "String"];
 
 t.VISITOR_KEYS = require("./visitor-keys");
 
@@ -66,6 +61,7 @@ each(t.FLIPPED_ALIAS_KEYS, function (types, type) {
 
 /**
  * Returns whether `node` is of given `type`.
+ *
  * For better performance, use this instead of `is[Type]` when `type` is unknown.
  * Optionally, pass `skipAliasCheck` to directly compare `node.type` with `type`.
  *
@@ -156,6 +152,9 @@ t.isFalsyExpression = function (node) {
  * declarations hoisted to the top of the current scope.
  *
  * Expression statements are just resolved to their standard expression.
+ *
+ * @param {Array} nodes
+ * @param {Scope} scope
  */
 
 t.toSequenceExpression = function (nodes, scope) {
@@ -185,17 +184,23 @@ t.toSequenceExpression = function (nodes, scope) {
   }
 };
 
-//
+/*
+ * Description
+ *
+ * @param {Object} actual
+ * @param {Object} expected
+ * @returns {Boolean}
+ */
 
 t.shallowEqual = function (actual, expected) {
   var keys = Object.keys(expected);
-  var key;
 
   for (var i = 0; i < keys.length; i++) {
-    key = keys[i];
+    var key = keys[i];
 
-    if (actual[key] !== expected[key])
+    if (actual[key] !== expected[key]) {
       return false;
+    }
   }
 
   return true;
@@ -330,7 +335,7 @@ t.isReferenced = function (node, parent) {
 };
 
 /**
- * Description
+ * Check if the input `node` is an `Identifier` and `isReferenced`.
  *
  * @param {Object} node
  * @param {Object} parent
@@ -342,7 +347,8 @@ t.isReferencedIdentifier = function (node, parent) {
 };
 
 /**
- * Description
+ * Check if the input `name` is a valid identifier name
+ * and isn't a reserved word.
  *
  * @param {String} name
  * @returns {Boolean}