--update: getAt(index)

Author: ashokdey

src/_DataStructures_/LinkedList/LinkedList.test.js

@@ -168,5 +168,26 @@ describe('Data Structures: Linked Lists', () => {
         expect(list.getFirst().data).toEqual(15);
       });
     });
+
+    describe('getAt(index)', () => {
+      beforeEach(() => {
+        list.addAtBeginning('Hello');
+        list.addAtEnd('There!');
+        list.addAtEnd('Welcome');
+      });
+      
+      it('Should return `null` for empty list regardless of index value', () => {
+        list.delete();
+        expect(list.getAt(10)).toEqual(null);
+      });
+
+      it('Should return the node for given index', () => {
+        expect(list.getAt(1).data).toEqual('There!');
+      });
+
+      it('Should return the last element for large index', () => {
+        expect(list.getAt(10).data).toEqual('Welcome');
+      });
+    });
   });
 });

src/_DataStructures_/LinkedList/index.js

@@ -21,11 +21,9 @@ class LinkedList {
       this.head = node;
     } else {
       let address = this.head;
-
       while (address.next) {
         address = address.next;
       }
-
       address.next = node;
     }
   }
@@ -71,6 +69,21 @@ class LinkedList {
     return address;
   }
 
+  getAt(index) {
+    if (!this.length()) {
+      return null;
+    }
+    let address = this.head;
+    let count = index;
+
+    while (count && address.next) {
+      address = address.next;
+      count -= 1;
+    }
+
+    return address;
+  }
+
   length() {
     let address = this.head;
     let count = 0;