diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ded37a0
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,44 @@
+# See https://docs.github.com/get-started/getting-started-with-git/ignoring-files for more about ignoring files.
+
+# Compiled output
+/dist
+/tmp
+/out-tsc
+/bazel-out
+
+# Node
+/node_modules
+npm-debug.log
+yarn-error.log
+
+# IDEs and editors
+.idea/
+.project
+.classpath
+.c9/
+*.launch
+.settings/
+*.sublime-workspace
+
+# Visual Studio Code
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+.history/*
+
+# Miscellaneous
+/.angular/cache
+.sass-cache/
+/connect.lock
+/coverage
+/libpeerconnection.log
+testem.log
+/typings
+
+# System files
+.DS_Store
+Thumbs.db
+*.ignore
+temp
\ No newline at end of file
diff --git a/README.md b/README.md
index db2113b..75da9cd 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,97 @@
-# core
-Main package. 
+<!-- <a href="https://www.typescriptlang.org/">
+  <img src="https://creazilla-store.fra1.digitaloceanspaces.com/icons/3257106/file-type-typescript-official-icon-md.png" width="20%" />
+</a> -->
+
+## typescript-package/core
+
+Core package.
+
+<!-- npm badge -->
+[![npm version][typescript-package-npm-badge-svg]][typescript-package-npm-badge]
+[![GitHub issues][typescript-package-badge-issues]][typescript-package-issues]
+[![GitHub license][typescript-package-badge-license]][typescript-package-license]
+
+<br>
+
+## Table of contents
+
+* [Installation](#installation)
+* [Api](#api)
+* [Git](#git)
+  * [Commit](#commit)
+  * [Versioning](#versioning)
+* [License](#license)
+
+## Installation
+
+```bash
+npm install @typescript-package/core
+```
+
+## Api
+
+```typescript
+import {
+  resultCallback,
+  typeOf
+} from '@typescript-package/core';
+```
+
+## GIT
+
+### Commit
+
+* [AngularJS Git Commit Message Conventions][git-commit-angular]
+* [Karma Git Commit Msg][git-commit-karma]
+* [Conventional Commits][git-commit-conventional]
+
+### Versioning
+
+[Semantic Versioning 2.0.0][git-semver]
+
+**Given a version number MAJOR.MINOR.PATCH, increment the:**
+
+* MAJOR version when you make incompatible API changes,
+* MINOR version when you add functionality in a backwards-compatible manner, and
+* PATCH version when you make backwards-compatible bug fixes.
+
+Additional labels for pre-release and build metadata are available as extensions to the MAJOR.MINOR.PATCH format.
+
+**FAQ**
+How should I deal with revisions in the 0.y.z initial development phase?
+
+> The simplest thing to do is start your initial development release at 0.1.0 and then increment the minor version for each subsequent release.
+
+How do I know when to release 1.0.0?
+
+> If your software is being used in production, it should probably already be 1.0.0. If you have a stable API on which users have come to depend, you should be 1.0.0. If you’re worrying a lot about backwards compatibility, you should probably already be 1.0.0.
+
+## License
+
+MIT © angular-package ([license][typescript-package-license])
+
+<!-- This package: typescript-package  -->
+  <!-- GitHub: badges -->
+  [typescript-package-badge-issues]: https://img.shields.io/github/issues/typescript-package/core
+  [typescript-package-badge-forks]: https://img.shields.io/github/forks/typescript-package/core
+  [typescript-package-badge-stars]: https://img.shields.io/github/stars/typescript-package/core
+  [typescript-package-badge-license]: https://img.shields.io/github/license/typescript-package/core
+  <!-- GitHub: badges links -->
+  [typescript-package-issues]: https://github.com/typescript-package/core/issues
+  [typescript-package-forks]: https://github.com/typescript-package/core/network
+  [typescript-package-license]: https://github.com/typescript-package/core/blob/master/LICENSE
+  [typescript-package-stars]: https://github.com/typescript-package/core/stargazers
+<!-- This package -->
+
+<!-- Package: typescript-package -->
+  <!-- npm -->
+  [typescript-package-npm-badge-svg]: https://badge.fury.io/js/%40typescript-package%2Fcore.svg
+  [typescript-package-npm-badge]: https://badge.fury.io/js/%40typescript-package%2Fcore
+
+<!-- GIT -->
+[git-semver]: http://semver.org/
+
+<!-- GIT: commit -->
+[git-commit-angular]: https://gist.github.com/stephenparish/9941e89d80e2bc58a153
+[git-commit-karma]: http://karma-runner.github.io/0.10/dev/git-commit-msg.html
+[git-commit-conventional]: https://www.conventionalcommits.org/en/v1.0.0/
diff --git a/ng-package.json b/ng-package.json
new file mode 100644
index 0000000..a29fbbc
--- /dev/null
+++ b/ng-package.json
@@ -0,0 +1,8 @@
+{
+  "$schema": "../../node_modules/ng-packagr/ng-package.schema.json",
+  "dest": "../../dist/core",
+  "lib": {
+    "entryFile": "src/public-api.ts"
+  },
+  "keepLifecycleScripts": true
+}
\ No newline at end of file
diff --git a/package-lock.json b/package-lock.json
new file mode 100644
index 0000000..a6a3453
--- /dev/null
+++ b/package-lock.json
@@ -0,0 +1,19 @@
+{
+  "name": "@testing-package/core",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "@testing-package/core",
+      "version": "1.0.0",
+      "funding": [
+        {
+          "type": "individual",
+          "url": "https://checkout.revolut.com/pay/048b10a3-0e10-42c8-a917-e3e9cb4c8e29"
+        }
+      ],
+      "license": "MIT"
+    }
+  }
+}
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..0de5a9b
--- /dev/null
+++ b/package.json
@@ -0,0 +1,35 @@
+{
+  "name": "@testing-package/core",
+  "version": "1.0.0",
+  "author": "wwwdev.io <dev@wwwdev.io>",
+  "description": "Core package.",
+  "license": "MIT",
+  "publishConfig": {
+    "access": "public",
+    "registry": "https://registry.npmjs.org"
+  },
+  "peerDependencies": {},
+  "scripts": {
+    "prepublishOnly": "npm run pkg && npm run clean",
+    "pkg": "npm pkg delete dependencies",
+    "clean": "npm pkg delete scripts"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/typescript-package/core.git"
+  },
+  "bugs": {
+    "url": "https://github.com/typescript-package/core/issues"
+  },
+  "keywords": [
+    "@typescript-package",
+    "@typescript-package/core"
+  ],
+  "funding": [
+    {
+      "type": "individual",
+      "url": "https://checkout.revolut.com/pay/048b10a3-0e10-42c8-a917-e3e9cb4c8e29"
+    }
+  ],
+  "sideEffects": false
+}
diff --git a/src/lib/index.ts b/src/lib/index.ts
new file mode 100644
index 0000000..f4b5f6d
--- /dev/null
+++ b/src/lib/index.ts
@@ -0,0 +1,3 @@
+// Function.
+export { resultCallback } from './result-callback.func';
+export { typeOf } from './type-of.func';
diff --git a/src/lib/result-callback.func.ts b/src/lib/result-callback.func.ts
new file mode 100644
index 0000000..af861c5
--- /dev/null
+++ b/src/lib/result-callback.func.ts
@@ -0,0 +1,6 @@
+/**
+ * @description Default function to handle `callback` of functions.
+ * @param {boolean} result - A value of `boolean` type of the result of the check.
+ * @returns {boolean} The returned value is a `boolean` of the result of the check.
+ */
+export const resultCallback = (result: boolean): boolean => result;
diff --git a/src/lib/type-of.func.ts b/src/lib/type-of.func.ts
new file mode 100644
index 0000000..cd49ce4
--- /dev/null
+++ b/src/lib/type-of.func.ts
@@ -0,0 +1,8 @@
+/**
+ * @description Gets the specific object class type of any value.
+ * @param {*} value Any value to check its object class type.
+ * @returns {string} The return value is a `string` of the object class name.
+ * @author https://javascript.plainenglish.io/the-best-way-to-type-check-in-vanilla-js-55197b4f45ec
+ */
+export const typeOf = (value: any): string =>
+  Object.prototype.toString.call(value).slice(8, -1).toLowerCase();
diff --git a/src/public-api.ts b/src/public-api.ts
new file mode 100644
index 0000000..a2cadfd
--- /dev/null
+++ b/src/public-api.ts
@@ -0,0 +1,4 @@
+/*
+ * Public API Surface of core
+ */
+export * from './lib';
\ No newline at end of file
diff --git a/ts-package-barcode-logo-512.png b/ts-package-barcode-logo-512.png
new file mode 100644
index 0000000..9705d19
Binary files /dev/null and b/ts-package-barcode-logo-512.png differ
diff --git a/tsconfig.lib.json b/tsconfig.lib.json
new file mode 100644
index 0000000..2359bf6
--- /dev/null
+++ b/tsconfig.lib.json
@@ -0,0 +1,15 @@
+/* To learn more about Typescript configuration file: https://www.typescriptlang.org/docs/handbook/tsconfig-json.html. */
+/* To learn more about Angular compiler options: https://angular.dev/reference/configs/angular-compiler-options. */
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../../out-tsc/lib",
+    "declaration": true,
+    "declarationMap": true,
+    "inlineSources": true,
+    "types": []
+  },
+  "exclude": [
+    "**/*.spec.ts"
+  ]
+}
diff --git a/tsconfig.lib.prod.json b/tsconfig.lib.prod.json
new file mode 100644
index 0000000..9215caa
--- /dev/null
+++ b/tsconfig.lib.prod.json
@@ -0,0 +1,11 @@
+/* To learn more about Typescript configuration file: https://www.typescriptlang.org/docs/handbook/tsconfig-json.html. */
+/* To learn more about Angular compiler options: https://angular.dev/reference/configs/angular-compiler-options. */
+{
+  "extends": "./tsconfig.lib.json",
+  "compilerOptions": {
+    "declarationMap": false
+  },
+  "angularCompilerOptions": {
+    "compilationMode": "partial"
+  }
+}
diff --git a/tsconfig.spec.json b/tsconfig.spec.json
new file mode 100644
index 0000000..254686d
--- /dev/null
+++ b/tsconfig.spec.json
@@ -0,0 +1,15 @@
+/* To learn more about Typescript configuration file: https://www.typescriptlang.org/docs/handbook/tsconfig-json.html. */
+/* To learn more about Angular compiler options: https://angular.dev/reference/configs/angular-compiler-options. */
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../../out-tsc/spec",
+    "types": [
+      "jasmine"
+    ]
+  },
+  "include": [
+    "**/*.spec.ts",
+    "**/*.d.ts"
+  ]
+}