diff --git a/05_hash_tables/ES6/02_check_voter.js b/05_hash_tables/ES6/02_check_voter.js
index d2aeeb1..1bf5d70 100644
--- a/05_hash_tables/ES6/02_check_voter.js
+++ b/05_hash_tables/ES6/02_check_voter.js
@@ -1,14 +1,18 @@
 const voted = {};
-const checkVoter = (name) => {
+
+/**
+ * Vote check
+ * @param {string} name Voter name
+ */
+const checkVoter = name => {
   if (voted[name]) {
-    console.log('kick them out!');
+    console.log("kick them out!");
   } else {
     voted[name] = true;
-    console.log('let them vote!');
+    console.log("let them vote!");
   }
 };
 
-
-checkVoter('tom'); // let them vote!
-checkVoter('mike'); // let them vote!
-checkVoter('mike'); // kick them out!
+checkVoter("tom"); // let them vote!
+checkVoter("mike"); // let them vote!
+checkVoter("mike"); // kick them out!
diff --git a/05_hash_tables/javascript/02_check_voter.js b/05_hash_tables/javascript/02_check_voter.js
index 288eba6..4f1c2c5 100644
--- a/05_hash_tables/javascript/02_check_voter.js
+++ b/05_hash_tables/javascript/02_check_voter.js
@@ -1,16 +1,20 @@
-'use strict';
+"use strict";
 
 const voted = {};
+
+/**
+ * Vote check
+ * @param {string} name Voter name
+ */
 function check_voter(name) {
   if (voted[name]) {
-    console.log('kick them out!');
+    console.log("kick them out!");
   } else {
     voted[name] = true;
-    console.log('let them vote!');
+    console.log("let them vote!");
   }
 }
 
-
 check_voter("tom"); // let them vote!
 check_voter("mike"); // let them vote!
 check_voter("mike"); // kick them out!
diff --git a/05_hash_tables/javascript/03_hashtable.js b/05_hash_tables/javascript/03_hashtable.js
index 7c02d9d..ceaeebe 100644
--- a/05_hash_tables/javascript/03_hashtable.js
+++ b/05_hash_tables/javascript/03_hashtable.js
@@ -1,173 +1,162 @@
 /**
  * Class HashTable
- *
- * @param {object} obj
+ * @param {Object} obj
  */
-let HashTable = function( obj ) {
-    let length = 0;
-    this._items = ( function( obj ) {
-        let items = {};
-        for ( let p in obj ) {
-                items[p] = obj[p];
-                length++;
-        }
-        return items;
-    }( obj ) );
+const HashTable = function(obj) {
+  let length = 0;
+  this._items = (function(obj) {
+    let items = {};
+    for (let p in obj) {
+      items[p] = obj[p];
+      length++;
+    }
+    return items;
+  })(obj);
 
-    /**
-     * Associates the specified value to the specified key
-     *
-     * @param {string} key The key to which associate the value
-     * @param {string} value The value to associate to the key
-     *
-     * @return {(undefined|object)} Undefined is object didn't exists before this call
-     */
-    this.set = function( key, value ) {
-        let previous = undefined;
+  /**
+   * Associates the specified value to the specified key
+   * @param {string} key The key to which associate the value
+   * @param {string} value The value to associate to the key
+   * @returns {(undefined|Object)} Undefined is object didn't exists before this call
+   */
+  this.set = function(key, value) {
+    let previous = undefined;
 
-        if ( this.has( key ) ) {
-            previous = this._items[key];
-        } else {
-            length++;
-        }
+    if (this.has(key)) {
+      previous = this._items[key];
+    } else {
+      length++;
+    }
 
-        this._items[key] = value;
+    this._items[key] = value;
 
-        return previous;
-    };
+    return previous;
+  };
 
-    /**
-     * Returns the value associated to the specified key
-     *
-     * @param {string} key The key from which retrieve the value
-     *
-     * @return {(undefined|string)} Undefined or associated value
-     */
-    this.get = function( key ) {
-        return this._items.hasOwnProperty( key ) ? this._items[key] : undefined;
-    };
+  /**
+   * Returns the value associated to the specified key
+   * @param {string} key The key from which retrieve the value
+   * @returns {(undefined|string)} Undefined or associated value
+   */
+  this.get = function(key) {
+    return this._items.hasOwnProperty(key) ? this._items[key] : undefined;
+  };
 
-    /**
-     * Returns whether the hashtable contains the specified key
-     *
-     * @param {string} key The key to check
-     *
-     * @return {boolean}
-     */
-    this.has = function( key ) {
-        return this._items.hasOwnProperty( key );
-    };
+  /**
+   * Returns whether the hashtable contains the specified key
+   * @param {string} key The key to check
+   * @returns {boolean}
+   */
+  this.has = function(key) {
+    return this._items.hasOwnProperty(key);
+  };
 
-    /**
-     * Removes the specified key with its value
-     *
-     * @param {string} key The key to remove
-     *
-     * @return {(undefined|string)} Undefined if key doesn't exist and
-     * string (previous value) - value of deleted item
-     */
-    this.remove = function( key ) {
-        if ( this.has( key ) ) {
-            let previous = this._items[key];
-            length--;
-            delete this._items[key];
-            return previous;
-        } else {
-            return undefined;
-        }
-    };
+  /**
+   * Removes the specified key with its value
+   * @param {string} key The key to remove
+   * @returns {(undefined|string)} Undefined if key doesn't exist and
+   * string (previous value) - value of deleted item
+   */
+  this.remove = function(key) {
+    if (this.has(key)) {
+      let previous = this._items[key];
+      length--;
+      delete this._items[key];
+      return previous;
+    } else {
+      return undefined;
+    }
+  };
 
-    /**
-     * Returns an array with all the registered keys
-     *
-     * @return {array}
-     */
-    this.getKeys = function() {
-        let keys = [];
+  /**
+   * Returns an array with all the registered keys
+   * @returns {Array}
+   */
+  this.getKeys = function() {
+    let keys = [];
 
-        for ( let i in this._items ) {
-            if ( this.has( i ) ) {
-                keys.push( i );
-            }
-        }
+    for (let i in this._items) {
+      if (this.has(i)) {
+        keys.push(i);
+      }
+    }
 
-        return keys;
-    };
+    return keys;
+  };
 
-    /**
-     * Returns an array with all the registered values
-     *
-     * @return {array}
-     */
-    this.getValues = function() {
-        let values = [];
+  /**
+   * Returns an array with all the registered values
+   * @returns {Array}
+   */
+  this.getValues = function() {
+    let values = [];
 
-        for ( let i in this._items ) {
-            if ( this.has( i ) ) {
-                values.push( this._items[i] );
-            }
-        }
+    for (let i in this._items) {
+      if (this.has(i)) {
+        values.push(this._items[i]);
+      }
+    }
 
-        return values;
-    };
+    return values;
+  };
 
-    /**
-     * Iterates all entries in the specified iterator callback
-     * @param {function} callback A method with 2 parameters: key, value
-     */
-    this.each = function( callback ) {
-        for ( let i in this._items ) {
-            if ( this.has( i ) ) {
-                callback( i, this._items[i] );
-            }
-        }
-    };
+  /**
+   * Iterates all entries in the specified iterator callback
+   * @param {function} callback A method with 2 parameters: key, value
+   */
+  this.each = function(callback) {
+    for (let i in this._items) {
+      if (this.has(i)) {
+        callback(i, this._items[i]);
+      }
+    }
+  };
 
-    /**
-     * Deletes all the key-value pairs on the hashmap
-     */
-    this.clear = function() {
-        this._items = {};
-        length = 0;
-    };
+  /**
+   * Deletes all the key-value pairs on the hashmap
+   */
+  this.clear = function() {
+    this._items = {};
+    length = 0;
+  };
 
-    /**
-     * Gets the count of the entries in the hashtable
-     */
-    Object.defineProperty( this, 'length', {
-        get: function() {
-            return length;
-        },
-    });
+  /**
+   * Gets the count of the entries in the hashtable
+   */
+  Object.defineProperty(this, "length", {
+    get: function() {
+      return length;
+    }
+  });
 
-    /**
-     * Gets an array of all keys in the hashtable
-     */
-    Object.defineProperty(this, 'keys', {
-        get: function() {
-            return this.getKeys();
-        },
-    });
+  /**
+   * Gets an array of all keys in the hashtable
+   */
+  Object.defineProperty(this, "keys", {
+    get: function() {
+      return this.getKeys();
+    }
+  });
 
-    /**
-     * Gets an array of all values in the hashtable
-     */
-    Object.defineProperty(this, 'values', {
-        get: function() {
-            return this.getValues();
-        },
-    });
+  /**
+   * Gets an array of all values in the hashtable
+   */
+  Object.defineProperty(this, "values", {
+    get: function() {
+      return this.getValues();
+    }
+  });
 };
 
-let hashtable = new HashTable({'one': 1, 'two': 2, 'three': 3, 'cuatro': 4});
+const hashtable = new HashTable({ one: 1, two: 2, three: 3, cuatro: 4 });
 
-console.log( 'Original length: ' + hashtable.length ); // Original length: 4
-console.log( 'Value of key "one": ' + hashtable.get( 'one' ) ); // Value of key "one": 1
-console.log( 'Has key "foo"? ' + hashtable.has( 'foo' )); // Has key "foo"? false
-console.log( 'Previous value of key "foo": ' + hashtable.set( 'foo', 'bar' ) ); // Previous value of key "foo": undefined
-console.log( 'Length after set: ' + hashtable.length ); // Length after set: 5
-console.log( 'Value of key "foo": ' + hashtable.get( 'foo' ) ); // Value of key "foo": bar
-console.log( 'Value of key "cuatro": ' + hashtable.get( 'cuatro' )); // Value of key "cuatro": 4
-console.log( 'Get keys by using property: ' + hashtable.keys ); // Get keys by using property: one,two,three,cuatro,foo
+console.log("Original length: " + hashtable.length); // Original length: 4
+console.log('Value of key "one": ' + hashtable.get("one")); // Value of key "one": 1
+console.log('Has key "foo"? ' + hashtable.has("foo")); // Has key "foo"? false
+console.log('Previous value of key "foo": ' + hashtable.set("foo", "bar")); // Previous value of key "foo": undefined
+console.log("Length after set: " + hashtable.length); // Length after set: 5
+console.log('Value of key "foo": ' + hashtable.get("foo")); // Value of key "foo": bar
+console.log('Value of key "cuatro": ' + hashtable.get("cuatro")); // Value of key "cuatro": 4
+console.log("Get keys by using property: " + hashtable.keys); // Get keys by using property: one,two,three,cuatro,foo
 hashtable.clear();
-console.log( 'Length after clear: ' + hashtable.length ); // Length after clear: 0
+console.log("Length after clear: " + hashtable.length); // Length after clear: 0