How to Build and Publish an Angular Library: 2025 Guide

Building and publishing an Angular library involves creating a reusable Angular project with the Angular CLI. Then, you develop your components or services before packaging and publishing the library to npm or a private registry. This approach enables you to share modular, maintainable code across multiple projects or with the wider community.

With over 1.2 million websites using Angular, building your own library is a great way to contribute scalable solutions and improve your development workflow. In this 2025 guide, you will learn each step from setup to publishing so you can confidently create and share your Angular library.

What Are Angular Libraries? Key Features Explained

A library is a collection of precompiled routines that a program can use. Similarly, Angular libraries are modular sets of code designed to encapsulate and reuse functionality across multiple Angular projects.

Creating an Angular library involves following specific steps to ensure smooth integration with other Angular applications, helping developers improve code organization, maintainability, and reusability.

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What’s New in Angular 18 (Released May 2024)?

Angular 18 brings several powerful updates and enhancements to streamline development and boost performance:

• Zoneless Change Detection: Improves performance by optimizing how Angular tracks changes in your app.
• New Developer Hub (Angular.dev): Centralized resource for comprehensive documentation and learning.
• Stable Features: Experimental features such as Material 3, Microsoft.net integration, deferrable views, Angular CLI improvements, and built-in control flow are now stable and production-ready.
• Server-Side Rendering (SSR) Improvements: Enhanced i18n hydration support and better debugging tools for SSR applications.
• Firebase Hosting Integration: Simplifies deployment and management of dynamic Angular applications with seamless Firebase integration.

These updates equip developers with the tools and resources needed to build efficient Angular libraries and applications in 2025.

Key Features of Angular

According to angular.io, Angular offers a robust set of features designed to streamline development and deliver high-performance applications across various platforms.

Here are some key features of Angular:

1. Cross-Platform Development Made Simple

Angular’s unified architecture allows developers to write code once and deploy it anywhere, whether it’s web browsers, mobile web, native mobile apps (using frameworks like Ionic or NativeScript), or native desktop applications (via Electron).
This cross-platform capability is powered by Angular’s modular design and platform-agnostic APIs, ensuring your components and services work consistently across targets.

2. Optimized Performance and Scalability

Angular maximizes runtime efficiency through several advanced techniques:

• Zoneless Change Detection: Minimizes overhead by removing the need for Angular Zones, reducing unnecessary change detection cycles and improving rendering speed.
• Web Workers: Offload heavy computations to background threads, keeping the UI responsive.
• Server-Side Rendering (Angular Universal): Pre-renders pages on the server to improve initial load times and SEO.
• Reactive Programming: Utilizing RxJS for managing asynchronous data streams allows efficient handling of complex data flows and event-driven interactions.
• Immutable Data Models: Using Immutable.js or similar libraries helps reduce unintended side effects and optimizes change detection.

3. Advanced Tooling and Developer Experience

Angular’s tooling ecosystem accelerates development:

• Angular CLI: Automates project scaffolding, build optimization, and deployment processes with commands that generate components, services, and libraries adhering to best practices.
• TypeScript Integration: Typescript provides static typing and modern ECMAScript features, catching errors at compile time and improving code maintainability.
• Declarative Templates: Simplify UI development with a powerful templating syntax, directives, and data binding mechanisms that reduce boilerplate code.
• IDE Support: Angular Language Service plugins for popular IDEs like VS Code and WebStorm provide real-time code completions, error detection, and seamless navigation tailored specifically for Angular projects, greatly enhancing developer productivity.

4. Enterprise-Grade Scalability and Adoption

Angular powers applications ranging from startups to enterprise-scale projects, including Google’s own products like Google Ads and Google Cloud Console. Its scalability stems from a well-architected framework that supports large teams working in modular codebases, backed by a strong community and ongoing Google stewardship.

Additionally, Angular libraries fully support the Life Cycle of Angular Components, ensuring that library-based components behave predictably and integrate seamlessly across platforms.

Also Read: Top 15 CSS Project Ideas for Beginners to Boost Your Resume in 2025

How to Build an Angular Library?

Creating an Angular library allows you to encapsulate reusable code, such as components, services, and pipes, and share it across multiple Angular applications. It promotes clean architecture, modular development, and maintainability.

Let us build a Library in Angular App step-by-step:
Step 1: Install Node.js:

• Angular requires Node.js version 14.X.X or later. You can download it from Nodejs.org.
  • The latest Version is: node-v16.13.1-x64
• Install node.js once downloaded:
• Once you have installed Node.js on your system, open node.js command prompt.
• To check your version, run node -v in a terminal/console window.

Step 2: Use npm to Install Angular CLI

• Use the following command to install Angular CLI

npm install -g @angular/cli

Or

npm install -g @angular/cli@latest

Or

• Just go to Angular CLI official website Angular.io.
• You will see the whole cli command to create an Angular app. You need to run the first command to install Angular CLI. These steps are the same for Windows and Mac.

• To check the Node and Angular CLI version, use ng --version command.

Step 3: Create an app called ngApp4Library

Syntax:

ng new app_name
C:\>ng new ngApp4Library

It asks for

Would you like to add Angular routing? Yes

Which stylesheet format would you like to use?

> CSS 

….

Step 4: Generate Library via CLI:

Syntax: for creating a Library

ng generate library <name> [options] ng g library <name> [options]

• Let us generate the required library: here we are going to create “my-lib” Library.
• Go to the app folder and install the required Library: “my-lib”:

ng generate library my-lb

• This will create a library project my-lib into our ngApp4library project.
• my-lib Library will contain library module, services, components, etc.

Step 5: Edit the library ts file: Give a functionality to your library

As you can see our library has its own module, service, and component. We can add more components, services, directives, pipes, and modules as per our needs.

The Library file that we need to edit is my-lib. It appears in the folder C:\Users\ISHU\Desktop -> ngApp4Library -> projects -> my-lib -> src -> lib. The file to be edited is:  my-lib.component.ts

Add the following code:

import { Component, OnInit } from '@angular/core';
@Component({
 selector: 'lib-my-lib',
 template: `
<form  method="post">
 <div >
   <label for = "username"> <b> Username: </b> </label>
   <input type = "text" placeholder = "Enter Username here" name = "username" style = "margin:10px;" required>
 <br/>
   <label for = "passwd"> <b> Password: </b> </label>
   <input type = "password" placeholder = "Enter Password here" name = "passwd" style = "margin:10px;" required>
 <br/>
    <button type = "submit"> Login </button>
</div>
</form>
 `,
 styles: [
 ]
})
export class MyLibComponent implements OnInit {
 constructor() { }
 ngOnInit(): void {
 }
}

Also Read: HTML Basics with Code Examples: A Quick Guide

Let’s begin rebuilding the app by utilizing powerful libraries to streamline development and enhance functionality

Rebuilding an App Using Libraries

Before consuming a library in your Angular app, you first need to create and build it properly. This process differs slightly depending on whether the library is for local use within the same application or for global use across multiple applications.

Here’s how to create a new library:

1. Build the library and consume it in the same application:

• To build the library, we run the following command to check angular version:

ng build <library name>

• Here our library name is my-lib, thus the command we need is: ng build my-lib

• The command will generate the library dist folder
• Next step is to implement the library into our current project: ngApp4Library:
• For this step, we need to import this library in our main app (ngApp4Library).
• In app.module.ts import my-lib library module as shown: app.module.ts:

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { MyLibModule } from 'my-lib';
@NgModule({
 declarations: [
   AppComponent
 ],
 imports: [
   BrowserModule,
   AppRoutingModule,
   MyLibModule
 ],
 providers: [],
 bootstrap: [AppComponent]
})
export class AppModule { }

• Now, we simply add the my-lib library in the HTML file.
• Please note that the selector for the library used here is: lib-my-lib
• To know about the selector (lib-my-lib), we can check the file: ngApp4Library -> projects -> my-lib -> src -> lib->  my-lib.component.ts
• Now open and edit: app.component.html from the main App folder: ngApp4Library\src\app\ app.component.html:

<lib-my-lib></lib-my-lib>

• Now we can start our application from the Node.js command line as: ng serve

• Open the favourite browser and type the default Angular app URL to check the output: localhost:4200/.

2. Rebuild the library and consume it from some other application:

We go through the following steps to implement the Library into another project:

• To Re-build the library, we run the following command:

ng build <library name>

• Here our library name is my-lib, thus the command we need is: ng build my-lib

• The command will generate the library dist folder
• Now, create a new Angular application: ngAppClient in a new command window. We need to let the library application run.

ng new ngAppClient

• Now from the build, check the paths destined as “to”

• Here, the “to” part gives us the value: C:\ Users\ ISHU\ Desktop\ ngApp4Library\ dist\ my-lib
• So, now copy this path: “C:\ Users\ ISHU\ Desktop\ ngApp4Library\ dist\ my-lib”
• Next, we open the terminal of ngAppClient project and install this library with the following command into the ngAppClient project: 
  • npm i C:\ Users\ ISHU\ Desktop\ ngApp4Library\ dist\ my-lib
  • C:\Users\ISHU\Desktop>cd ngAppClient
  • C:\Users\ISHU\Desktop\ngAppClient>npm i
  • C:\Users\ISHU\Desktop\ngApp4Library\dist\my-lib

• After installation of the library in the client application, we can import the library into the app.module.ts of the client app. After importing the library module, we can easily use those services, components, etc.
• To use the library:
  • Open Client Project -> app.module.ts file and edit it to add the library:

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { MyLibModule } from 'my-lib';
@NgModule({
 declarations: [
   AppComponent
 ],
 imports: [
   BrowserModule,
   AppRoutingModule,
   MyLibModule
 ],
 providers: [],
 bootstrap: [AppComponent]
})
export class AppModule { }

• Now, we simply add the my-lib library in the client project app.component.html file.
• Please note that the selector for the library used here is: lib-my-lib
• To know about the selector (lib-my-lib), we can check the file: ngApp4Library -> projects -> my-lib -> src -> lib->  my-lib.component.ts
• And then open and edit: app.component.html from the client App folder: ngAppClient\ src\ app\ app.component.html:

<lib-my-lib></lib-my-lib>

• We can now start our client application for the Node.js command line as:

ng serve.

• In case the Library project is running in the default port, 4200, we can change the port of the client app to 5200 by the following command:

ng serve --port 5200

• Open your favorite browser and type the default Angular app URL to check the output: localhost:5200/.

Also Read: Top 25+ HTML Project Ideas for Beginners in 2025: Source Code, Career Insights, and More

Let’s get started with publishing your Angular library to npm, so you can share your reusable code with the world

How to Publish an Angular Library to npm?

We publish the library to make the library available on npm. To create an angular library and publish it, all we need to do is create a production build, and then run the npm publish command from the library project’s dist directory.

The Syntax is as follows:

ng build <library name> --prod
cd dist/<library name>
npm publish

Here the Library project is ngApp4library, and the library is my-lib, so we run the following commands:

ng build my-lib --prod
cd dist/my-lib
npm publish

If you have not published anything before, you will need to create an npm account first and log in into your npm account and then publish your library.

Also Read: How to Install Node.js and NPM on Windows? [Step-by-Step]

How Angular Libraries Enhance Code Reusability and Efficiency?

An Angular library acts like a pre-built code module, containing reusable components, services, or even entire functionalities. Unlike full applications, libraries can't run on their own. They can be imported and integrated into your projects. Think of them as Lego sets for Angular.

These libraries tackle challenges you'd face in any application, such as:

• Building User Interfaces: Angular libraries offer pre-built, customizable UI components that speed up development. They ensure consistency, accessibility, and responsiveness across your app’s design.
• Presenting Data: These libraries provide tools for displaying data efficiently with features like sorting, filtering, and pagination. This makes complex datasets easy to view and interact with.
• Handling User Input: Angular libraries simplify managing forms and user input with built-in validation and reactive controls. They help ensure data accuracy while enhancing the user experience.

The Angular community and the Angular team create these libraries to address these needs with well-tested and reusable solutions.

Building a library is as simple as creating a regular Angular project. Once done, you can publish it as an npm package.

Popular Angular Library Examples Include:

• ReactiveFormsModule, which helps you build reactive forms.
• Service worker library, used to create Progressive Web Apps (PWAs).
• Angular Material, offering a large collection of beautiful and flexible UI components.

By utilizing existing libraries or building your own, you can accelerate your workflow, maintain high code quality, and focus more on delivering value rather than reinventing the wheel.

Let’s take a closer look at how to create an Angular library and make reusable modules for your projects.

Key Purpose and Benefits of Angular Libraries

Angular libraries provide a structured way to package and distribute reusable Angular modules, components, directives, pipes, and services. They facilitate modular development by separating concerns and promoting encapsulation, which is critical for scaling large applications and maintaining code consistency across multiple projects.

Creating libraries also enables independent versioning and deployment, allowing teams to update shared codebases without tightly coupling applications.

Here are the key benefits of Angular libraries:

• Modular Architecture: Libraries bundle Angular modules and dependencies into Angular Package Format (APF), enabling seamless integration and tree-shaking to reduce bundle size.
• Encapsulation of Features: Isolate components, services, and utilities with clear public APIs, minimizing side effects and enhancing code maintainability.
• Version Control & Distribution: Publish libraries to package registries (e.g., npm), enabling semantic versioning and dependency management across projects.
• Build and Compilation Optimization: Use Angular CLI and ng-packagr to build libraries with Ahead-of-Time (AOT) compilation, ensuring compatibility and performance.
• Dependency Management: Define peer dependencies explicitly to avoid duplication and conflicts in host applications.
• Consistent API Surface: Enforce strict public API exposure via public-api.ts to control what consumers can access, improving security and stability.

Also Read: Web Application Architecture: Function, Components, Types & Real Life Examples

Common Use Cases for Angular Libraries

If you’re developing multiple Angular projects, it’s often a smart move to build an Angular library to centralize reusable code. Angular libraries are essentially pre-built components like windows and doors that you can "plug and play" into your applications. Instead of rewriting the same functionality for every new project, you can build an Angular library with components tailored to your needs and reuse them wherever necessary.

These libraries find applications in a variety of scenarios, offering key benefits such as:

• Code Reusability:

  When you build an Angular library, you can share common components and services across multiple projects, reducing redundancy. For example, consider UI elements like navigation bars, login forms, or styled buttons. Rather than creating these from scratch each time, store them in a library and reuse them across apps, just like having a box of building blocks ready to go.

• Maintainability:

  One major advantage when you build an Angular library is the ease of maintaining your code. Updates made to the library automatically reflect in all dependent applications. This eliminates the pain of manually updating features across multiple projects. It’s like having a master switch that controls settings everywhere.

• Collaboration:

  Building a shared library ensures that your team works with consistent components and coding standards. When you build an Angular library, you create a common framework that everyone on the team can rely on. It’s like speaking the same design language. Collaboration becomes smoother and more efficient.

Here are a few practical examples where Angular libraries can be beneficial.

Example 1: If you're working on multiple Angular projects, and you want to maintain consistency in the UI components across these projects then you can create a shared UI components library. 

• Step 1: Library creation 
  • $ ng generate library shared-components 
• Step 2:  Library Usage (In Angular): 

Example 2: Imagine that you have multiple Angular projects that require authentication. You want to maintain a consistent authentication mechanism.  

• Step 1: Library creation 
  • $ ng generate library auth 
• Step 2: Library Implementation 
• Step 3: Library Usage (In Angular): 

Example 3: Let’s say that you want to create a reusable feature module for handling file uploads.  

• Step 1: Library creation:
  • $ ng generate library file-upload 
• Step 2: Library Implementation: 
• Step 3: Library Usage (In Angular): 

// AuthService in 'auth' library
export class AuthService f
// Authentication logic

Also Read: How to Install Angular CLI in Windows 10

Enhance Your Skills: Learn to Build Angular Libraries with upGrad!

Creating and publishing an Angular library involves initializing a reusable Angular project with the CLI, building your components or services, and then packaging and publishing the library to npm or a private repository. This process enables seamless sharing and reuse of code across multiple projects.

Staying up-to-date with Angular’s latest updates, like Angular 18, is crucial to take advantage of improved performance and new capabilities. upGrad’s learning programs help you stay ahead by equipping you with the skills to build and publish Angular libraries efficiently using the most current tools and best practices.

To further enhance your tech journey, here are a few additional courses recommended to complement your Angular skills. While not directly related to Angular, these courses can help broaden your expertise in related areas.

• Node.js For Beginners
• Programming with Python: Introduction for Beginners
• AI-Driven Full-Stack Development

Ready to choose the ideal Angular course for your 2025 goals? Receive personalized counseling and valuable insights from upGrad, or visit your nearest upGrad offline center for more details

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