Make it possible to use custom comparators for linked lists.

src/data-structures/linked-list/LinkedList.js

@@ -1,12 +1,18 @@
 import LinkedListNode from './LinkedListNode';
+import Comparator from '../../utils/comparator/Comparator';
 
 export default class LinkedList {
-  constructor() {
+  /**
+   * @param {Function} [comparatorFunction]
+   */
+  constructor(comparatorFunction) {
     /** @var LinkedListNode */
     this.head = null;
 
     /** @var LinkedListNode */
     this.tail = null;
+
+    this.compare = new Comparator(comparatorFunction);
   }
 
   /**
@@ -54,7 +60,7 @@ export default class LinkedList {
     let deletedNode = null;
 
     // If the head must be deleted then make 2nd node to be a head.
-    if (this.head.value === value) {
+    if (this.compare.equal(this.head.value, value)) {
       deletedNode = this.head;
       this.head = this.head.next;
     }
@@ -63,7 +69,7 @@ export default class LinkedList {
 
     // If next node must be deleted then make next node to be a next next one.
     while (currentNode.next) {
-      if (currentNode.next.value === value) {
+      if (this.compare.equal(currentNode.next.value, value)) {
         deletedNode = currentNode.next;
         currentNode.next = currentNode.next.next;
       } else {
@@ -72,7 +78,7 @@ export default class LinkedList {
     }
 
     // Check if tail must be deleted.
-    if (this.tail.value === value) {
+    if (this.compare.equal(this.tail.value, value)) {
       this.tail = currentNode;
     }
 
@@ -99,7 +105,7 @@ export default class LinkedList {
       }
 
       // If value is specified then try to compare by value..
-      if (value !== undefined && currentNode.value === value) {
+      if (value !== undefined && this.compare.equal(currentNode.value, value)) {
         return currentNode;
       }
 

src/data-structures/linked-list/__test__/LinkedList.test.js

@@ -175,4 +175,30 @@ describe('LinkedList', () => {
     expect(node.value.key).toBe('test2');
     expect(linkedList.find({ callback: value => value.key === 'test5' })).toBeNull();
   });
+
+  it('should find node by means of custom compare function', () => {
+    const comparatorFunction = (a, b) => {
+      if (a.customValue === b.customValue) {
+        return 0;
+      }
+
+      return a.customValue < b.customValue ? -1 : 1;
+    };
+
+    const linkedList = new LinkedList(comparatorFunction);
+
+    linkedList
+      .append({ value: 1, customValue: 'test1' })
+      .append({ value: 2, customValue: 'test2' })
+      .append({ value: 3, customValue: 'test3' });
+
+    const node = linkedList.find({
+      value: { value: 2, customValue: 'test2' },
+    });
+
+    expect(node).toBeDefined();
+    expect(node.value.value).toBe(2);
+    expect(node.value.customValue).toBe('test2');
+    expect(linkedList.find({ value: 2, customValue: 'test5' })).toBeNull();
+  });
 });