1 files changed, 71 insertions, 68 deletions
diff --git a/lib/internal/DoublyLinkedList.js b/lib/internal/DoublyLinkedList.js
index 86c5cfd..259ac0d 100644
--- a/lib/internal/DoublyLinkedList.js
+++ b/lib/internal/DoublyLinkedList.js
@@ -2,86 +2,89 @@
 // used for queues. This implementation assumes that the node provided by the user can be modified
 // to adjust the next and last properties. We implement only the minimal functionality
 // for queue support.
-export default function DLL() {
-    this.head = this.tail = null;
-    this.length = 0;
-}
-
-function setInitial(dll, node) {
-    dll.length = 1;
-    dll.head = dll.tail = node;
-}
+export default class DLL {
+    constructor() {
+        this.head = this.tail = null;
+        this.length = 0;
+    }
 
-DLL.prototype.removeLink = function(node) {
-    if (node.prev) node.prev.next = node.next;
-    else this.head = node.next
-    if (node.next) node.next.prev = node.prev;
-    else this.tail = node.prev;
+    removeLink(node) {
+        if (node.prev) node.prev.next = node.next;
+        else this.head = node.next
+        if (node.next) node.next.prev = node.prev;
+        else this.tail = node.prev;
 
-    node.prev = node.next = null;
-    this.length -= 1;
-    return node;
-}
+        node.prev = node.next = null;
+        this.length -= 1;
+        return node;
+    }
 
-DLL.prototype.empty = function () {
-    while(this.head) this.shift();
-    return this;
-};
+    empty () {
+        while(this.head) this.shift();
+        return this;
+    }
 
-DLL.prototype.insertAfter = function(node, newNode) {
-    newNode.prev = node;
-    newNode.next = node.next;
-    if (node.next) node.next.prev = newNode;
-    else this.tail = newNode;
-    node.next = newNode;
-    this.length += 1;
-}
+    insertAfter(node, newNode) {
+        newNode.prev = node;
+        newNode.next = node.next;
+        if (node.next) node.next.prev = newNode;
+        else this.tail = newNode;
+        node.next = newNode;
+        this.length += 1;
+    }
 
-DLL.prototype.insertBefore = function(node, newNode) {
-    newNode.prev = node.prev;
-    newNode.next = node;
-    if (node.prev) node.prev.next = newNode;
-    else this.head = newNode;
-    node.prev = newNode;
-    this.length += 1;
-}
+    insertBefore(node, newNode) {
+        newNode.prev = node.prev;
+        newNode.next = node;
+        if (node.prev) node.prev.next = newNode;
+        else this.head = newNode;
+        node.prev = newNode;
+        this.length += 1;
+    }
 
-DLL.prototype.unshift = function(node) {
-    if (this.head) this.insertBefore(this.head, node);
-    else setInitial(this, node);
-};
+    unshift(node) {
+        if (this.head) this.insertBefore(this.head, node);
+        else setInitial(this, node);
+    }
 
-DLL.prototype.push = function(node) {
-    if (this.tail) this.insertAfter(this.tail, node);
-    else setInitial(this, node);
-};
+    push(node) {
+        if (this.tail) this.insertAfter(this.tail, node);
+        else setInitial(this, node);
+    }
 
-DLL.prototype.shift = function() {
-    return this.head && this.removeLink(this.head);
-};
+    shift() {
+        return this.head && this.removeLink(this.head);
+    }
 
-DLL.prototype.pop = function() {
-    return this.tail && this.removeLink(this.tail);
-};
+    pop() {
+        return this.tail && this.removeLink(this.tail);
+    }
 
-DLL.prototype.toArray = function () {
-    var arr = Array(this.length);
-    var curr = this.head;
-    for(var idx = 0; idx < this.length; idx++) {
-        arr[idx] = curr.data;
-        curr = curr.next;
+    toArray () {
+        var arr = Array(this.length);
+        var curr = this.head;
+        for(var idx = 0; idx < this.length; idx++) {
+            arr[idx] = curr.data;
+            curr = curr.next;
+        }
+        return arr;
     }
-    return arr;
-}
 
-DLL.prototype.remove = function (testFn) {
-    var curr = this.head;
-    while(!!curr) {
-        var next = curr.next;
-        if (testFn(curr)) {
-            this.removeLink(curr);
+    remove (testFn) {
+        var curr = this.head;
+        while(curr) {
+            var next = curr.next;
+            if (testFn(curr)) {
+                this.removeLink(curr);
+            }
+            curr = next;
         }
-        curr = next;
+        return this;
     }
-    return this;
 }
+
+function setInitial(dll, node) {
+    dll.length = 1;
+    dll.head = dll.tail = node;
+}
+