Started working on Linked Lists

Author: linux-nerd

src/linked-list/linked-list.js

@@ -0,0 +1,43 @@
+export class Node {
+  constructor(key, next = null) {
+    this._key = key;
+    this._next = next;
+  }
+
+  get key() {
+    return this._key
+  }
+  get next() {
+    return this._next;
+  }
+}
+
+
+const _size = Symbol('size');
+const _head = Symbol('head');
+
+export class LinkedList {
+  constructor() {
+    this[_size] = 0;
+    this[_head] = null;
+  }
+
+  get head() {
+    return this[_head];
+  }
+
+  size() {
+    return this[_size];
+  }
+
+  isEmpty() {
+    return this.size() === 0;
+  }
+
+  search(item) { }
+  insertLast(item) { }
+  insertFirst(item) { }
+  insertBefore(item, before) { }
+  insertAfter(item, after) { }
+  remove(item) { }
+}

src/linked-list/linked-list.spec.js

@@ -0,0 +1,15 @@
+import { LinkedList } from './linked-list';
+
+describe('Linked List', () => {
+  let list;
+  beforeEach(() => {
+    list = new LinkedList
+  });
+
+  it('should create a linked list object', () => {
+    expect(list).toBeDefined();
+    expect(list.size()).toBe(0);
+    expect(list.head).toBe(null);
+    expect(list.isEmpty()).toBeTruthy();
+  });
+});

src/test-index.js

@@ -1,4 +1,5 @@
 require('./binary-search-tree/binary-search-tree.spec');
 require('./graph/graph.spec');
-require('./queue/queue.spec');
 require('./graph/adj-list.spec');
+require('./queue/queue.spec');
+require('./linked-list/linked-list.spec');

typings/data-structures.d.ts

@@ -34,8 +34,14 @@ declare namespace DataStructures {
     enqueue(o): void;
     dequeue(): Error | void;
     size(): number;
-    isEmpty(): void;
+    isEmpty(): boolean;
     top(): any;
     clear(): void;
   }
+
+  class LinkedList {
+    head(): any;
+    size(): number;
+    isEmpty(): boolean;
+  }
 }