diff --git a/.github/workflows/ci-test.yml b/.github/workflows/ci-test.yml
index 8644915..2c4c91a 100755
--- a/.github/workflows/ci-test.yml
+++ b/.github/workflows/ci-test.yml
@@ -7,18 +7,17 @@ on: [push, pull_request]
 
 jobs:
   test:
-
     runs-on: ubuntu-latest
 
     strategy:
       matrix:
-        deno-version: [1.44.4]
+        deno-version: [2.x.x]
 
     steps:
       - name: Git Checkout Deno Module
         uses: actions/checkout@v4
       - name: Use Deno Version ${{ matrix.deno-version }}
-        uses: denoland/setup-deno@v1
+        uses: denoland/setup-deno@v2
         with:
           deno-version: ${{ matrix.deno-version }}
       - name: format check
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
index 102df5a..61206c1 100644
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@@ -2,12 +2,12 @@ name: "CodeQL"
 
 on:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
     # The branches below must be a subset of the branches above
-    branches: [ main ]
+    branches: [main]
   schedule:
-    - cron: '33 18 * * 3'
+    - cron: "33 18 * * 3"
 
 jobs:
   analyze:
@@ -21,39 +21,39 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        language: [ 'javascript' ]
+        language: ["javascript"]
         # CodeQL supports [ 'cpp', 'csharp', 'go', 'java', 'javascript', 'python', 'ruby' ]
         # Learn more about CodeQL language support at https://aka.ms/codeql-docs/language-support
 
     steps:
-    - name: Checkout repository
-      uses: actions/checkout@v4
-
-    # Initializes the CodeQL tools for scanning.
-    - name: Initialize CodeQL
-      uses: github/codeql-action/init@v2
-      with:
-        languages: ${{ matrix.language }}
-        # If you wish to specify custom queries, you can do so here or in a config file.
-        # By default, queries listed here will override any specified in a config file.
-        # Prefix the list here with "+" to use these queries and those in the config file.
-        # queries: ./path/to/local/query, your-org/your-repo/queries@main
-
-    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
-    # If this step fails, then you should remove it and run the build manually (see below)
-    - name: Autobuild
-      uses: github/codeql-action/autobuild@v2
-
-    # ℹ️ Command-line programs to run using the OS shell.
-    # 📚 See https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idstepsrun
-
-    # ✏️ If the Autobuild fails above, remove it and uncomment the following three lines
-    #    and modify them (or add more) to build your code if your project
-    #    uses a compiled language
-
-    #- run: |
-    #   make bootstrap
-    #   make release
-
-    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v2
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      # Initializes the CodeQL tools for scanning.
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v2
+        with:
+          languages: ${{ matrix.language }}
+          # If you wish to specify custom queries, you can do so here or in a config file.
+          # By default, queries listed here will override any specified in a config file.
+          # Prefix the list here with "+" to use these queries and those in the config file.
+          # queries: ./path/to/local/query, your-org/your-repo/queries@main
+
+      # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
+      # If this step fails, then you should remove it and run the build manually (see below)
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@v2
+
+      # ℹ️ Command-line programs to run using the OS shell.
+      # 📚 See https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idstepsrun
+
+      # ✏️ If the Autobuild fails above, remove it and uncomment the following three lines
+      #    and modify them (or add more) to build your code if your project
+      #    uses a compiled language
+
+      #- run: |
+      #   make bootstrap
+      #   make release
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v2
diff --git a/README.md b/README.md
index 4e45c2f..86912da 100755
--- a/README.md
+++ b/README.md
@@ -113,12 +113,12 @@ for (let i = 0; i < 5; i++) {
 
 ```html
 <script type="module">
-import { genid } from "https://esm.sh/@ndaidong/bellajs";
-// import { genid } from 'https://unpkg.com/@ndaidong/bellajs/esm/mod.js';
+  import { genid } from "https://esm.sh/@ndaidong/bellajs";
+  // import { genid } from 'https://unpkg.com/@ndaidong/bellajs/esm/mod.js';
 
-for (let i = 0; i < 5; i++) {
-  console.log(genid());
-}
+  for (let i = 0; i < 5; i++) {
+    console.log(genid());
+  }
 </script>
 ```
 
diff --git a/deno.json b/deno.json
index 697c5b2..4f395aa 100644
--- a/deno.json
+++ b/deno.json
@@ -1,6 +1,6 @@
 {
   "name": "@ndaidong/bellajs",
-  "version": "12.0.0",
+  "version": "12.0.1",
   "description": "A useful helper for any javascript program",
   "homepage": "https://github.com/ndaidong/bellajs",
   "repository": {
diff --git a/mod.ts b/mod.ts
index 5f7e1cb..7be2d4c 100644
--- a/mod.ts
+++ b/mod.ts
@@ -1,11 +1,58 @@
 // mod.ts
 
-import { hasProperty, isArray, isObject, isString } from "./utils/detection.ts";
+import {
+  hasProperty,
+  isArray,
+  isDate,
+  isObject,
+  isString,
+} from "./utils/detection.ts";
 
 export type AnyObject = { [key: string]: any };
 
-export const clone = (val: AnyObject): AnyObject => {
-  return structuredClone(val);
+export const clone = (val: any, history: any = null): any => {
+  const stack = history || new Set();
+
+  if (stack.has(val)) {
+    return val;
+  }
+
+  stack.add(val);
+
+  if (isDate(val)) {
+    return new Date(val.valueOf());
+  }
+
+  const copyObject = (o: any): any => {
+    const oo = Object.create({});
+    for (const k in o) {
+      if (hasProperty(o, k)) {
+        oo[k] = clone(o[k], stack);
+      }
+    }
+    return oo;
+  };
+
+  const copyArray = (a: any): any => {
+    return [...a].map((e: any): any => {
+      if (isArray(e)) {
+        return copyArray(e);
+      } else if (isObject(e)) {
+        return copyObject(e);
+      }
+      return clone(e, stack);
+    });
+  };
+
+  if (isArray(val)) {
+    return copyArray(val);
+  }
+
+  if (isObject(val)) {
+    return copyObject(val);
+  }
+
+  return val;
 };
 
 export function copies(
diff --git a/tests/random_test.ts b/tests/random_test.ts
index 9a10e01..03f7a2e5b 100644
--- a/tests/random_test.ts
+++ b/tests/random_test.ts
@@ -19,13 +19,21 @@ Deno.test("check if .randint() works correctly", async (t) => {
     assertEquals(q, 10);
   });
 
-  const min = 50;
-  const max = 80;
-  await t.step(`.randint() between ${min} - ${max}`, () => {
-    for (let i = 0; i < 100; i++) {
-      const q = randint(min, max);
-      assertEquals(q >= min, true);
-      assertEquals(q <= max, true);
+  await t.step(`.randint() in the range of [min, max]`, () => {
+    for (let i = 0; i < 1000; i++) {
+      const q = randint(0, 10);
+      assertEquals(q >= 0, true);
+      assertEquals(q <= 10, true);
+    }
+    for (let i = 0; i < 1000; i++) {
+      const q = randint(100, 1000);
+      assertEquals(q >= 100, true);
+      assertEquals(q <= 1000, true);
+    }
+    for (let i = 0; i < 1000; i++) {
+      const q = randint(0, 10000);
+      assertEquals(q >= 0, true);
+      assertEquals(q <= 10000, true);
     }
   });
 });
diff --git a/utils/random.ts b/utils/random.ts
index b10f26c..94fb572 100755
--- a/utils/random.ts
+++ b/utils/random.ts
@@ -16,8 +16,8 @@ export const genid = (len: number = 32, prefix: string = ""): string => {
 };
 
 export const randint = (min: number = 0, max: number = 1e6): number => {
-  const byteArray = new Uint8Array(1);
+  const byteArray = new Uint32Array(1);
   crypto.getRandomValues(byteArray);
-  const floatNum = Number("0." + byteArray[0].toString());
-  return Math.floor(floatNum * (max - min + 1)) + min;
+  const randomNumber = byteArray[0] / (0xffffffff + 1);
+  return Math.floor(randomNumber * (max - min + 1)) + min;
 };