adding removeFirst and removeLast method

Author: mamenesia

linkedList/linkedList.js

@@ -49,6 +49,34 @@ class LinkedList {
     clear() {
       this.head = null;
     }
+
+    removeFirst() {
+      if(!this.head) {
+        return;
+      }
+
+      this.head = this.head.next;
+    }
+
+    removeLast() {
+      
+      if(!this.head) {
+        return;
+      } else if(!this.head.next) {
+        previous = null;
+        return;
+      }
+
+      let previous = this.head;
+      let node = this.head.next;
+
+      while(node.next) {
+        previous = node;
+        node = node.next;
+      }
+
+      previous.next = null;
+    }
   }
 }