added LinkedList class in ES6 syntax

Author: loiane

chapter05/01-LinkedList2.js

@@ -0,0 +1,157 @@
+let LinkedList2 = (function () {
+
+    class Node {
+        constructor(element, priority){
+            this.element = element;
+            this.next = null;
+        }
+    }
+
+    let length = 0;
+    let head = null;
+
+    class LinkedList2 {
+
+        append(element) {
+
+            let node = new Node(element),
+                current;
+
+            if (head === null) { //first node on list
+                head = node;
+            } else {
+
+                current = head;
+
+                //loop the list until find last item
+                while (current.next) {
+                    current = current.next;
+                }
+
+                //get last item and assign next to added item to make the link
+                current.next = node;
+            }
+
+            length++; //update size of list
+        }
+
+        insert(position, element) {
+
+            //check for out-of-bounds values
+            if (position >= 0 && position <= length) {
+
+                let node = new Node(element),
+                    current = head,
+                    previous,
+                    index = 0;
+
+                if (position === 0) { //add on first position
+
+                    node.next = current;
+                    head = node;
+
+                } else {
+                    while (index++ < position) {
+                        previous = current;
+                        current = current.next;
+                    }
+                    node.next = current;
+                    previous.next = node;
+                }
+
+                length++; //update size of list
+
+                return true;
+
+            } else {
+                return false;
+            }
+        }
+
+        removeAt(position) {
+
+            //check for out-of-bounds values
+            if (position > -1 && position < length) {
+
+                let current = head,
+                    previous,
+                    index = 0;
+
+                //removing first item
+                if (position === 0) {
+                    head = current.next;
+                } else {
+
+                    while (index++ < position) {
+
+                        previous = current;
+                        current = current.next;
+                    }
+
+                    //link previous with current's next - skip it to remove
+                    previous.next = current.next;
+                }
+
+                length--;
+
+                return current.element;
+
+            } else {
+                return null;
+            }
+        }
+
+        remove(element) {
+
+            let index = this.indexOf(element);
+            return this.removeAt(index);
+        }
+
+        indexOf(element) {
+
+            let current = head,
+                index = 0;
+
+            while (current) {
+                if (element === current.element) {
+                    return index;
+                }
+                index++;
+                current = current.next;
+            }
+
+            return -1;
+        }
+
+        isEmpty() {
+            return length === 0;
+        }
+
+        size() {
+            return length;
+        }
+
+        getHead() {
+            return head;
+        }
+
+        toString() {
+
+            let current = head,
+                string = '';
+
+            while (current) {
+                string += current.element + (current.next ? '\n' : '');
+                current = current.next;
+            }
+            return string;
+
+        }
+
+        print() {
+            console.log(this.toString());
+        }
+    }
+
+    return LinkedList2;
+})();

chapter05/02-UsingLinkedLists.js

@@ -1,4 +1,4 @@
-let list = new LinkedList2();
+let list = new LinkedList();
 list.append(15);
 list.print();
 console.log(list.indexOf(15));