Add new hash table methods.

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

@@ -17,7 +17,7 @@ describe('HashTable', () => {
     expect(hashTable.hash('abc')).toBe(6);
   });
 
-  it('should insert, read and delete data with collisions', () => {
+  it('should set, read and delete data with collisions', () => {
     const hashTable = new HashTable(3);
 
     expect(hashTable.hash('a')).toBe(1);
@@ -25,11 +25,15 @@ describe('HashTable', () => {
     expect(hashTable.hash('c')).toBe(0);
     expect(hashTable.hash('d')).toBe(1);
 
-    hashTable.insert('a', 'sky-old');
-    hashTable.insert('a', 'sky');
-    hashTable.insert('b', 'sea');
-    hashTable.insert('c', 'earth');
-    hashTable.insert('d', 'ocean');
+    hashTable.set('a', 'sky-old');
+    hashTable.set('a', 'sky');
+    hashTable.set('b', 'sea');
+    hashTable.set('c', 'earth');
+    hashTable.set('d', 'ocean');
+
+    expect(hashTable.has('x')).toBeFalsy();
+    expect(hashTable.has('b')).toBeTruthy();
+    expect(hashTable.has('c')).toBeTruthy();
 
     const stringifier = value => `${value.key}:${value.value}`;
 
@@ -47,18 +51,38 @@ describe('HashTable', () => {
     expect(hashTable.get('a')).toBeNull();
     expect(hashTable.get('d')).toBe('ocean');
 
-    hashTable.insert('d', 'ocean-new');
+    hashTable.set('d', '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' });
+    hashTable.set('objectKey', { prop1: 'a', prop2: 'b' });
 
     const object = hashTable.get('objectKey');
     expect(object).toBeDefined();
     expect(object.prop1).toBe('a');
     expect(object.prop2).toBe('b');
   });
+
+  it('should track actual keys', () => {
+    const hashTable = new HashTable(3);
+
+    hashTable.set('a', 'sky-old');
+    hashTable.set('a', 'sky');
+    hashTable.set('b', 'sea');
+    hashTable.set('c', 'earth');
+    hashTable.set('d', 'ocean');
+
+    expect(hashTable.getKeys()).toEqual(['a', 'b', 'c', 'd']);
+    expect(hashTable.has('a')).toBeTruthy();
+    expect(hashTable.has('x')).toBeFalsy();
+
+    hashTable.delete('a');
+
+    expect(hashTable.has('a')).toBeFalsy();
+    expect(hashTable.has('b')).toBeTruthy();
+    expect(hashTable.has('x')).toBeFalsy();
+  });
 });