diff --git a/src/data-structures/base/iterable-entry-base.ts b/src/data-structures/base/iterable-entry-base.ts
index 85b1446..f2c84a3 100644
--- a/src/data-structures/base/iterable-entry-base.ts
+++ b/src/data-structures/base/iterable-entry-base.ts
@@ -197,7 +197,7 @@ export abstract class IterableEntryBase<K = any, V = any> {
    * the provided callback function. If no element satisfies the callback function, `undefined` is
    * returned.
    */
-  find(callbackfn: EntryCallback<K, V, [K, V]>, thisArg?: any): [K, V] | undefined {
+  find(callbackfn: EntryCallback<K, V, boolean>, thisArg?: any): [K, V] | undefined {
     let index = 0;
     for (const item of this) {
       const [key, value] = item;
diff --git a/test/unit/data-structures/hash/hash-map.test.ts b/test/unit/data-structures/hash/hash-map.test.ts
index 55326a0..7269577 100644
--- a/test/unit/data-structures/hash/hash-map.test.ts
+++ b/test/unit/data-structures/hash/hash-map.test.ts
@@ -122,6 +122,8 @@ describe('HashMap', () => {
     it('should add a key-value pair', () => {
       hashMap.set('key1', 'value1');
       expect(hashMap.get('key1')).toBe('value1');
+      expect(hashMap.hasValue('value1')).toBe(true);
+      expect(hashMap.hasValue('value2')).toBe(false);
     });
 
     it('should handle object keys correctly', () => {
@@ -302,7 +304,7 @@ describe('HashMap', () => {
   });
 
   describe('HashMap HOF', () => {
-    let hashMap: HashMap;
+    let hashMap: HashMap<string, string>;
 
     beforeEach(() => {
       hashMap = new HashMap<string, string>();
@@ -339,6 +341,63 @@ describe('HashMap', () => {
       const result = hashMap.reduce((acc, value) => acc + value, '');
       expect(result).toBe('value1value2value3');
     });
+
+    it('should spread in an array', () => {
+      expect([...hashMap]).toEqual([
+        ['key1', 'value1'],
+        ['key2', 'value2'],
+        ['key3', 'value3']
+      ]);
+    });
+
+    it('should find', () => {
+      const found = hashMap.find(value => value === 'value1');
+      expect(found).toEqual(['key1', 'value1']);
+      const notFound = hashMap.find(value => value === 'value6');
+      expect(notFound).toEqual(undefined);
+    });
+
+    it('should every', () => {
+      const isEvery = hashMap.every(value => value.substring(0, 5) === 'value');
+      expect(isEvery).toEqual(true);
+      const isEvery4 = hashMap.every(value => value.substring(0, 4) === 'value');
+      expect(isEvery4).toEqual(false);
+    });
+
+    it('should some', () => {
+      const isSome = hashMap.some(value => value.substring(5, 6) === '2');
+      expect(isSome).toEqual(true);
+      const isSome4 = hashMap.some(value => value.substring(0, 5) === 'value');
+      expect(isSome4).toEqual(true);
+    });
+
+    it('should forEach', () => {
+      hashMap.forEach((value, key, index) => expect(value.substring(5, 6)).toBe(String(index + 1)));
+    });
+
+    it('should entries', () => {
+      const entries = hashMap.entries();
+      expect(entries.next()).toEqual({ done: false, value: ['key1', 'value1'] });
+      expect(entries.next()).toEqual({ done: false, value: ['key2', 'value2'] });
+      expect(entries.next()).toEqual({ done: false, value: ['key3', 'value3'] });
+      expect(entries.next()).toEqual({ done: true, value: undefined });
+    });
+
+    it('should keys', () => {
+      const keys = hashMap.keys();
+      expect(keys.next()).toEqual({ done: false, value: 'key1' });
+      expect(keys.next()).toEqual({ done: false, value: 'key2' });
+      expect(keys.next()).toEqual({ done: false, value: 'key3' });
+      expect(keys.next()).toEqual({ done: true, value: undefined });
+    });
+
+    it('should values', () => {
+      const values = hashMap.values();
+      expect(values.next()).toEqual({ done: false, value: 'value1' });
+      expect(values.next()).toEqual({ done: false, value: 'value2' });
+      expect(values.next()).toEqual({ done: false, value: 'value3' });
+      expect(values.next()).toEqual({ done: true, value: undefined });
+    });
   });
 });
 
diff --git a/test/unit/data-structures/stack/stack.test.ts b/test/unit/data-structures/stack/stack.test.ts
index ede31ac..a19a2d0 100644
--- a/test/unit/data-structures/stack/stack.test.ts
+++ b/test/unit/data-structures/stack/stack.test.ts
@@ -144,4 +144,15 @@ describe('Stack iterative methods', () => {
     expect(stack.size).toBe(4);
     expect([...stack]).toEqual([1, 2, 5, 3]);
   });
+
+  it('should iterable-element-base toElementFn', () => {
+    const stack = new Stack<{ key: number }>([1, 2, 5, 3], { toElementFn: key => ({ key }) });
+    expect([...stack]).toEqual([{ key: 1 }, { key: 2 }, { key: 5 }, { key: 3 }]);
+    expect(() => {
+      new Stack<{ key: number }>([1, 2, 5, 3], {
+        // @ts-ignore
+        toElementFn: {}
+      });
+    }).toThrow('toElementFn must be a function type');
+  });
 });