diff --git a/.eslintrc.js b/.eslintrc.js
index 8a44df5..3b46646 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -1,9 +1,14 @@
 module.exports = {
+  "parser": "@typescript-eslint/parser",
+  "plugins": [
+    "import",
+    "@typescript-eslint"
+  ],
   "extends": [
     "plugin:@typescript-eslint/recommended",
     "prettier"
   ],
-  ignorePatterns: ["lib/", "dist/", "umd/", "coverage/", "docs/"],
+  "ignorePatterns": ["lib/", "dist/", "umd/", "coverage/", "docs/"],
   "rules": {
     "import/no-anonymous-default-export": "off",
     "@typescript-eslint/no-unused-vars": "error",
@@ -39,9 +44,6 @@ module.exports = {
       }
     ]
   },
-  "plugins": [
-    "import"
-  ],
   "settings": {
     "import/parsers": {
       "@typescript-eslint/parser": [
diff --git a/package.json b/package.json
index 292e221..f40e5f1 100644
--- a/package.json
+++ b/package.json
@@ -17,6 +17,7 @@
     "build:commonjs": "rm -rf dist && tsc --project tsconfig.prod.json",
     "build:umd": "webpack",
     "build:docs": "typedoc --out docs ./src",
+    "check": "tsc --noEmit",
     "lint:src": "eslint --fix 'src/**/*.{js,ts}'",
     "lint:test": "eslint --fix 'test/**/*.{js,ts}'",
     "lint": "npm run lint:src && npm run lint:test",
diff --git a/src/data-structures/binary-tree/binary-tree.ts b/src/data-structures/binary-tree/binary-tree.ts
index 4f1e942..fef5769 100644
--- a/src/data-structures/binary-tree/binary-tree.ts
+++ b/src/data-structures/binary-tree/binary-tree.ts
@@ -13,7 +13,6 @@ import type {
   BinaryTreeNodeProperty,
   BinaryTreeOptions
 } from '../../types';
-import {IBinaryTree} from '../../interfaces';
 import {
   BinaryTreeDeletedResult,
   BinaryTreeNodePropertyName,
@@ -22,6 +21,7 @@ import {
   LoopType,
   NodeOrPropertyName
 } from '../../types';
+import {IBinaryTree} from '../../interfaces';
 import {trampoline} from '../../utils';
 
 export class BinaryTreeNode<V = any, FAMILY extends BinaryTreeNode<V, FAMILY> = BinaryTreeNodeNested<V>> {
@@ -574,7 +574,7 @@ export class BinaryTree<N extends BinaryTreeNode<N['val'], N> = BinaryTreeNode>
   /**
    * The function `getLeftMost` returns the leftmost node in a binary tree, starting from a specified node or the root if
    * no node is specified.
-   * generic type representing a node in a binary tree), `BinaryTreeNodeKey` (a type representing the ID of a binary tree
+   * generic type representing a node in a binary tree, `BinaryTreeNodeKey` (a type representing the ID of a binary tree
    * node), or `null`.
    * @returns The function `getLeftMost` returns the leftmost node in a binary tree. If the `beginRoot` parameter is
    * provided, it starts the traversal from that node. If `beginRoot` is not provided or is `null`, it starts the traversal
diff --git a/src/data-structures/heap/heap.ts b/src/data-structures/heap/heap.ts
index c6e0afd..4205333 100644
--- a/src/data-structures/heap/heap.ts
+++ b/src/data-structures/heap/heap.ts
@@ -5,13 +5,14 @@
  * @license MIT License
  */
 
-import type {HeapComparator, HeapDFSOrderPattern} from '../../types';
+import type {Comparator} from '../../types';
+import {DFSOrderPattern} from '../../types';
 
 export class Heap<E> {
   protected nodes: E[] = [];
-  private readonly comparator: HeapComparator<E>;
+  private readonly comparator: Comparator<E>;
 
-  constructor(comparator: HeapComparator<E>) {
+  constructor(comparator: Comparator<E>) {
     this.comparator = comparator;
   }
 
@@ -158,7 +159,7 @@ export class Heap<E> {
    * @param order - Traversal order parameter: 'in' (in-order), 'pre' (pre-order) or 'post' (post-order).
    * @returns An array containing elements traversed in the specified order.
    */
-  dfs(order: HeapDFSOrderPattern): E[] {
+  dfs(order: DFSOrderPattern): E[] {
     const result: E[] = [];
 
     // Auxiliary recursive function, traverses the binary heap according to the traversal order
@@ -227,7 +228,7 @@ export class Heap<E> {
    * @param comparator - Comparison function.
    * @returns A new Heap instance.
    */
-  static heapify<E>(nodes: E[], comparator: HeapComparator<E>): Heap<E> {
+  static heapify<E>(nodes: E[], comparator: Comparator<E>): Heap<E> {
     const binaryHeap = new Heap<E>(comparator);
     binaryHeap.nodes = [...nodes];
     binaryHeap.fix(); // Fix heap properties
diff --git a/src/data-structures/heap/max-heap.ts b/src/data-structures/heap/max-heap.ts
index 410b166..55ace08 100644
--- a/src/data-structures/heap/max-heap.ts
+++ b/src/data-structures/heap/max-heap.ts
@@ -7,11 +7,11 @@
  */
 
 import {Heap} from './heap';
-import type {HeapComparator} from '../../types';
+import type {Comparator} from '../../types';
 
 export class MaxHeap<E = any> extends Heap<E> {
   constructor(
-    comparator: HeapComparator<E> = (a: E, b: E) => {
+    comparator: Comparator<E> = (a: E, b: E) => {
       if (!(typeof a === 'number' && typeof b === 'number')) {
         throw new Error('The a, b params of compare function must be number');
       } else {
diff --git a/src/data-structures/heap/min-heap.ts b/src/data-structures/heap/min-heap.ts
index 2998199..fcc809b 100644
--- a/src/data-structures/heap/min-heap.ts
+++ b/src/data-structures/heap/min-heap.ts
@@ -7,11 +7,11 @@
  */
 
 import {Heap} from './heap';
-import type {HeapComparator} from '../../types';
+import type {Comparator} from '../../types';
 
 export class MinHeap<E = any> extends Heap<E> {
   constructor(
-    comparator: HeapComparator<E> = (a: E, b: E) => {
+    comparator: Comparator<E> = (a: E, b: E) => {
       if (!(typeof a === 'number' && typeof b === 'number')) {
         throw new Error('The a, b params of compare function must be number');
       } else {
diff --git a/src/data-structures/priority-queue/max-priority-queue.ts b/src/data-structures/priority-queue/max-priority-queue.ts
index 2418a76..49f016e 100644
--- a/src/data-structures/priority-queue/max-priority-queue.ts
+++ b/src/data-structures/priority-queue/max-priority-queue.ts
@@ -6,11 +6,11 @@
  * @license MIT License
  */
 import {PriorityQueue} from './priority-queue';
-import type {HeapComparator} from '../../types';
+import type {Comparator} from '../../types';
 
 export class MaxPriorityQueue<E = any> extends PriorityQueue<E> {
   constructor(
-    compare: HeapComparator<E> = (a: E, b: E) => {
+    compare: Comparator<E> = (a: E, b: E) => {
       if (!(typeof a === 'number' && typeof b === 'number')) {
         throw new Error('The a, b params of compare function must be number');
       } else {
diff --git a/src/data-structures/priority-queue/min-priority-queue.ts b/src/data-structures/priority-queue/min-priority-queue.ts
index 9635a1d..0e1b3e8 100644
--- a/src/data-structures/priority-queue/min-priority-queue.ts
+++ b/src/data-structures/priority-queue/min-priority-queue.ts
@@ -6,11 +6,11 @@
  * @license MIT License
  */
 import {PriorityQueue} from './priority-queue';
-import type {HeapComparator} from '../../types';
+import type {Comparator} from '../../types';
 
 export class MinPriorityQueue<E = any> extends PriorityQueue<E> {
   constructor(
-    compare: HeapComparator<E> = (a: E, b: E) => {
+    compare: Comparator<E> = (a: E, b: E) => {
       if (!(typeof a === 'number' && typeof b === 'number')) {
         throw new Error('The a, b params of compare function must be number');
       } else {
diff --git a/src/data-structures/priority-queue/priority-queue.ts b/src/data-structures/priority-queue/priority-queue.ts
index 9f4585c..2bc2769 100644
--- a/src/data-structures/priority-queue/priority-queue.ts
+++ b/src/data-structures/priority-queue/priority-queue.ts
@@ -7,10 +7,10 @@
  */
 
 import {Heap} from '../heap';
-import {HeapComparator} from '../../types';
+import {Comparator} from '../../types';
 
 export class PriorityQueue<E> extends Heap<E> {
-  constructor(comparator: HeapComparator<E>) {
+  constructor(comparator: Comparator<E>) {
     super(comparator);
   }
 }
diff --git a/src/types/data-structures/binary-tree.ts b/src/types/data-structures/binary-tree.ts
index a5f8f04..a296960 100644
--- a/src/types/data-structures/binary-tree.ts
+++ b/src/types/data-structures/binary-tree.ts
@@ -26,8 +26,6 @@ export type BinaryTreeNodePropertyName = 'key' | 'val';
 
 export type NodeOrPropertyName = 'node' | BinaryTreeNodePropertyName;
 
-export type DFSOrderPattern = 'in' | 'pre' | 'post';
-
 export type BinaryTreeNodeKey = number;
 
 export type BinaryTreeNodeProperty<N extends BinaryTreeNode<N['val'], N>> =
diff --git a/src/types/data-structures/heap.ts b/src/types/data-structures/heap.ts
index 55bf2b6..cb0ff5c 100644
--- a/src/types/data-structures/heap.ts
+++ b/src/types/data-structures/heap.ts
@@ -1,3 +1 @@
-export type HeapComparator<T> = (a: T, b: T) => number;
-
-export type HeapDFSOrderPattern = 'pre' | 'in' | 'post';
+export {};
diff --git a/src/types/helpers.ts b/src/types/helpers.ts
index cb0ff5c..f1991de 100644
--- a/src/types/helpers.ts
+++ b/src/types/helpers.ts
@@ -1 +1,4 @@
-export {};
+export type Comparator<T> = (a: T, b: T) => number;
+
+// export enum DFSOrderPattern {'pre' = 'pre', 'in' = 'in', 'post' = 'post'}
+export type DFSOrderPattern = 'pre' | 'in' | 'post';
diff --git a/test/unit/data-structures/heap/max-heap.test.ts b/test/unit/data-structures/heap/max-heap.test.ts
index 744406f..b6dd044 100644
--- a/test/unit/data-structures/heap/max-heap.test.ts
+++ b/test/unit/data-structures/heap/max-heap.test.ts
@@ -1,7 +1,7 @@
-import {HeapComparator, MaxHeap} from '../../../../src';
+import {Comparator, MaxHeap} from '../../../../src';
 
 describe('MaxHeap', () => {
-  const numberComparator: HeapComparator<number> = (a, b) => b - a;
+  const numberComparator: Comparator<number> = (a, b) => b - a;
   let maxHeap: MaxHeap<number>;
 
   beforeEach(() => {
diff --git a/test/unit/data-structures/heap/min-heap.test.ts b/test/unit/data-structures/heap/min-heap.test.ts
index 2425162..be8d548 100644
--- a/test/unit/data-structures/heap/min-heap.test.ts
+++ b/test/unit/data-structures/heap/min-heap.test.ts
@@ -1,7 +1,7 @@
-import {HeapComparator, MinHeap} from '../../../../src';
+import {Comparator, MinHeap} from '../../../../src';
 
 describe('MinHeap', () => {
-  const numberComparator: HeapComparator<number> = (a, b) => a - b;
+  const numberComparator: Comparator<number> = (a, b) => a - b;
   let minHeap: MinHeap<number>;
 
   beforeEach(() => {