diff --git a/src/searching/binarysearch.js b/src/searching/binarysearch.js
index efe6e28c..660ff265 100644
--- a/src/searching/binarysearch.js
+++ b/src/searching/binarysearch.js
@@ -1,9 +1,8 @@
 (function (exports) {
   'use strict';
 
-  function id (val) { return val; }
-  function get (key) { return function (val) { return val[key]; }; }
-
+  const id = (val) => val;
+  const get = (key) => (val) => val[key];
   /**
    * Searches for specific element in a given array using
    * the binary search algorithm.<br><br>
@@ -21,14 +20,14 @@
    * @param {Number} value Value of the element which index should be found.
    * @returns {Number} Index of the element or -1 if not found.
    */
-  function binarySearch(array, value, key) {
+  const binarySearch = (array, value, key) => {
     key = !key ? id : typeof key === 'string' ? get(key) : key;
     value = key(value);
-    var middle = Math.floor(array.length / 2);
-    var left = 0;
-    var right = array.length;
+    let middle = Math.floor(array.length / 2);
+    let left = 0;
+    let right = array.length;
     while (right >= left) {
-      var middleValue = key(array[middle]);
+      const middleValue = key(array[middle]);
       if (middleValue === value) {
         return middle;
       } else if (middleValue > value) {
@@ -39,8 +38,7 @@
       middle = Math.floor((left + right) / 2);
     }
     return -1;
-  }
-
+  };
   exports.binarySearch = binarySearch;
 
 })(typeof window === 'undefined' ? module.exports : window);
diff --git a/src/searching/knuth-morris-pratt.js b/src/searching/knuth-morris-pratt.js
index b4aeb85b..d395bd55 100644
--- a/src/searching/knuth-morris-pratt.js
+++ b/src/searching/knuth-morris-pratt.js
@@ -1,14 +1,17 @@
 (function (exports) {
   'use strict';
 
-  var kmp = (function () {
-    function builtKMPTable(str) {
-      var res = [];
-      var len;
-      var front;
-      var end;
-      var found;
-      for (var i = 1; i <= str.length; i += 1) {
+  const kmp = (str, substr) => {
+    if (str === substr) {
+      return 0;
+    }
+    const builtKMPTable = (str) => {
+      const res = [];
+      let len;
+      let front;
+      let end;
+      let found;
+      for (let i = 1; i <= str.length; i += 1) {
         front = Math.max(1, i - ((res[i - 2] || 0) + 1));
         end = Math.min(i - 1, (res[i - 2] || 0) + 1);
         found = false;
@@ -25,7 +28,7 @@
         res[i - 1] = len;
       }
       return res;
-    }
+    };
 
     /**
      * Knuth–Morris–Pratt algorithm. Searches for the position of
@@ -45,35 +48,29 @@
      * where the specified substring occurs for the first
      * time, or -1 if it never occurs.
      */
-    function indexOf(str, substr) {
-      if (str === substr) {
-        return 0;
+
+    const table = builtKMPTable(substr);
+    let i = 0;
+    let j = 0;
+    while (i < str.length) {
+      if (str[i] === substr[j]) {
+        i += 1;
+        j += 1;
       }
-      var table = builtKMPTable(substr);
-      var i = 0;
-      var j = 0;
-      while (i < str.length) {
-        if (str[i] === substr[j]) {
+      if (j === substr.length) {
+        return i - j;
+      }
+      if (i < str.length && str[i] !== substr[j]) {
+        if (j > 0 && table[j - 1] !== 0) {
+          j = table[j - 1];
+        } else {
           i += 1;
-          j += 1;
-        }
-        if (j === substr.length) {
-          return i - j;
-        }
-        if (i < str.length && str[i] !== substr[j]) {
-          if (j > 0 && table[j - 1] !== 0) {
-            j = table[j - 1];
-          } else {
-            i += 1;
-            j = 0;
-          }
+          j = 0;
         }
       }
-      return -1;
     }
-    return indexOf;
-  }());
-
+    return -1;
+  };
   exports.kmp = kmp;
-
 })(typeof window === 'undefined' ? module.exports : window);
+