diff --git a/lib/is.js b/lib/is.js
index 94b868a8..43e052c9 100644
--- a/lib/is.js
+++ b/lib/is.js
@@ -69,7 +69,7 @@ const number = function (val) {
  * @private
  */
 const integer = function (val) {
-  return number(val) && val % 1 === 0;
+  return Number.isInteger(val);
 };
 
 /**
@@ -85,7 +85,7 @@ const inRange = function (val, min, max) {
  * @private
  */
 const inArray = function (val, list) {
-  return list.indexOf(val) !== -1;
+  return list.includes(val);
 };
 
 /**