improvements to linkedlist

Author: amejiarosario

src/linked-list/linkedlist.js

@@ -13,27 +13,32 @@ class LinkedList {
 
   /**
    * Add element to the tail
-   * @param data
+   * @param dataOrNode
    * @returns {Node}
    */
-  addLast(data){
-    const node = getNode(data);
+  addLast(dataOrNode){
+    let node = getNode(dataOrNode);
     if(this.head) {
       this.tail.next = node;
     } else {
       this.head = node;
     }
-    this.tail = node;
-    this.length++;
+
+    while(node) {
+      this.tail = node;
+      this.length++;
+      if(!node.next) { break; }
+      node = node.next;
+    }
     return node;
   }
 
   /**
    * Add element to the head
    * @param data
    */
-  addFirst(data) {
-    const node = getNode(data);
+  addFirst(dataOrNode) {
+    const node = getNode(dataOrNode);
     if(this.head) {
       node.next = this.head;
     } else {
@@ -45,8 +50,8 @@ class LinkedList {
   }
 
   // O(1)
-  add(data) {
-    return this.addFirst(data);
+  add(dataOrNode) {
+    return this.addFirst(dataOrNode);
   }
 
   // O(n)

src/linked-list/linkedlist.spec.js

@@ -20,6 +20,18 @@ describe('LinkedList', function () {
     it('should have a size of 4', function () {
       expect(list.size()).to.equal(4);
     });
+
+    it('should add nodes and update the tail and size', function () {
+      const list2 = new LinkedList();
+      const a = list2.addLast('a');
+      list2.addLast('b');
+      const c = list2.addLast('c');
+
+      list.addLast(a);
+      expect(list.toString()).to.equal('1 -> 2 -> 3 -> 4 -> a -> b -> c');
+      expect(list.size()).to.equal(7);
+      expect(list.tail).to.equal(c);
+    });
   });
 
   describe('.addFirst', function () {