Make it possible to add objects to LinkedList.

src/data-structures/hash-table/HashTable.js

@@ -21,16 +21,32 @@ export default class HashTable {
 
   insert(key, value) {
     const bucketLinkedList = this.buckets[this.hash(key)];
-    bucketLinkedList.appendUnique({ key, value });
+    const node = bucketLinkedList.find({ callback: nodeValue => nodeValue.key === key });
+
+    if (!node) {
+      // Insert new node.
+      bucketLinkedList.append({ key, value });
+    } else {
+      // Update value of existing node.
+      node.value.value = value;
+    }
   }
 
   delete(key) {
     const bucketLinkedList = this.buckets[this.hash(key)];
-    return bucketLinkedList.deleteByKey(key);
+    const node = bucketLinkedList.find({ callback: nodeValue => nodeValue.key === key });
+
+    if (node) {
+      return bucketLinkedList.delete(node.value);
+    }
+
+    return null;
   }
 
   get(key) {
     const bucketLinkedList = this.buckets[this.hash(key)];
-    return bucketLinkedList.findByKey(key);
+    const node = bucketLinkedList.find({ callback: nodeValue => nodeValue.key === key });
+
+    return node ? node.value.value : null;
   }
 }

src/data-structures/hash-table/__test__/HashTable.test.js

@@ -31,19 +31,34 @@ describe('HashTable', () => {
     hashTable.insert('c', 'earth');
     hashTable.insert('d', 'ocean');
 
-    expect(hashTable.buckets[0].toString()).toBe('c:earth');
-    expect(hashTable.buckets[1].toString()).toBe('a:sky,d:ocean');
-    expect(hashTable.buckets[2].toString()).toBe('b:sea');
+    const stringifier = value => `${value.key}:${value.value}`;
 
-    expect(hashTable.get('a').value).toBe('sky');
-    expect(hashTable.get('d').value).toBe('ocean');
+    expect(hashTable.buckets[0].toString(stringifier)).toBe('c:earth');
+    expect(hashTable.buckets[1].toString(stringifier)).toBe('a:sky,d:ocean');
+    expect(hashTable.buckets[2].toString(stringifier)).toBe('b:sea');
+
+    expect(hashTable.get('a')).toBe('sky');
+    expect(hashTable.get('d')).toBe('ocean');
 
     hashTable.delete('a');
 
+    expect(hashTable.delete('not-existing')).toBeNull();
+
     expect(hashTable.get('a')).toBeNull();
-    expect(hashTable.get('d').value).toBe('ocean');
+    expect(hashTable.get('d')).toBe('ocean');
 
     hashTable.insert('d', 'ocean-new');
-    expect(hashTable.get('d').value).toBe('ocean-new');
+    expect(hashTable.get('d')).toBe('ocean-new');
+  });
+
+  it('should be possible to add objects to hash table', () => {
+    const hashTable = new HashTable();
+
+    hashTable.insert('objectKey', { prop1: 'a', prop2: 'b' });
+
+    const object = hashTable.get('objectKey');
+    expect(object).toBeDefined();
+    expect(object.prop1).toBe('a');
+    expect(object.prop2).toBe('b');
   });
 });