Generator-angular2-library NPM

generator-angular-2-library

Yeoman generator to create a standalone Angular library in seconds.

If you want to create an Angular library with directives, services and/or pipes, then this generator is just what you need.

This generator aligns with the official Angular Package Format and automatically generates a Flat ES Module, a UMD bundle, a single metadata.json and type definitions to make your library ready for AOT compilation by the consuming Angular application.

Watch Jason Aden's talk to learn more about the Angular Package Format.

More specifically, the latest version of this generator:

supports Angular 5
creates and configures package.json for the development of your library
creates and configures a second package.json for the distribution of your library
creates and configures tsconfig.json for your editor during development
creates and configures tslint.json for linting purposes
creates and configures .gitignore, .npmignore and .travis.yml
creates the main library file, a sample directive, a sample component, a sample service and a sample pipe
configures tslint for you with codelyzer support
creates and configures build scripts to generate a Flat ES Module (FESM), type definitions and metadata files for your library to make it ready for AOT compilation
creates and configures build scripts to generate a Universal Module Definition (UMD) bundle to use your library in Node.js, SystemJS and with script tags (Plunker, Fiddle, etc)
inlines templates automatically for you so you can use external HTML templates
inlines styles automatically for you so you can use external CSS templates
supports .scss files
supports unit tests and code coverage using jest

This generator is built for Angular version 2 and above, hence the name generator-angular2-library. If you are looking for a similar generator for AngularJS 1.x, please visit generator-angularjs-library.

Quick start

generator-angular2-library-v10

First, install Yeoman and generator-angular2-library using npm (assuming you already have node.js pre-installed).

$ npm install -g yo
$ npm install -g generator-angular2-library

make a new directory and cd into it:

$ mkdir angular-library-name
$ cd angular-library-name

and generate your new library:

$ yo angular2-library

The generator will prompt you for:

? Your full name: Jurgen Van de Moere
? Your email address: jurgen.van.de.moere@gmail.com
? Your library name (kebab case): angular-library-name
? Git repository url: https://github.com/jvandemo/angular2-library-name

and create the following files for you:

.
├── README.MD
├── gulpfile.js
├── package.json
├── src
│   ├── index.ts
│   ├── package.json
│   ├── sample.component.ts
│   ├── sample.directive.ts
│   ├── sample.pipe.ts
│   ├── sample.service.ts
│   └── tsconfig.es5.json
├── tsconfig.json
└── tslint.json

You can then add or edit *.ts files in the src/ directory and run:

$ npm run build

to automatically create all *.js, *.d.ts and *.metadata.json files in the dist directory:

dist
├── index.d.ts                  # Typings for AOT compilation
├── index.js                    # Flat ES Module (FESM) for use with webpack
├── lib.d.ts                    # Typings for AOT compilation
├── lib.metadata.json           # Metadata for AOT compilation
├── lib.umd.js                  # UMD bundle for use with Node.js, SystemJS or script tag
├── package.json                # package.json for consumer of your library
├── sample.component.d.ts       # Typings for AOT compilation
├── sample.directive.d.ts       # Typings for AOT compilation
├── sample.pipe.d.ts            # Typings for AOT compilation
└── sample.service.d.ts         # Typings for AOT compilation

Finally you publish your library to NPM by publishing the contents of the dist directory:

$ npm publish dist

TypeScript config

The generator creates 2 TypeScript config files:

tsconfig.json is used to configure your editor during development and is not used for building your library
src/tsconfig.es5.json is used by the Angular compiler to build the files in the dist directory when you run npm run build

Linting your code

Your library comes pre-configured with tslint and codelyzer support. To lint your code:

$ npm run lint

Building your library

From the root of your library directory, run:

$ npm run build

This will generate a dist directory with:

a package.json file specifically for distribution with Angular listed in the peerDependencies
sample-library.js: a Flat ES Module (FESM) file that contains all your library code in a single file
sample-library.umd.js: a Universal Module Definition (UMD) bundle file that contains all your library code in UMD format for use in Node.js, SystemJS or via a script tag (e.g. in Plunker, Fiddle, etc)
*.d.ts: type definitions for you library
sample-library.metadata.json: metadata for your library to support AOT compilation

Generating documentation for your library

From the root of your library directory, run:

$ npm run docs:build

This will generate a docs directory with all documentation of your library.

To serve your documentation, run:

$ npm run docs:serve

and navigate your browser to http://localhost:8080.

To automatically rebuild your documentation every time a file in the src directory changes, run:

$ npm run docs:watch

For more features, check out the compodoc website.

Publishing your library to NPM

To publish your library to NPM, first generate the dist directory:

$ npm run build

and then publish the contents of the dist directory to NPM:

$ npm publish dist

Consuming your library

Once you have published your library to the NPM registry, you can import it in any Angular application by first installing it using NPM:

$ npm install sample-library # use the name you used to publish to npm

and then importing your library in your Angular AppModule (or whatever module you wish to import your library into):

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppComponent } from './app.component';

// Import your library
import { SampleModule } from 'sample-library';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    
    // Specify your library as an import
    SampleModule.forRoot()
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Once your shared library is imported, you can use its components, directives and pipes in your Angular application templates:

<!-- app.component.html -->
<h1>{{ title }}</h1>
<sample-component>
  This component is part of the shared library and will now work as expected.
</sample-component>

and if you need to access a service from your shared library, you can inject it using Dependency Injection:

import { Component } from '@angular/core';

// Import the shared service
import { SampleService } from 'sample-library';

@Component({
  template: 'Injecting a service from the shared library'
})
export class HomeComponent {

  // Inject the service using Angular DI 
  constructor(private sampleService: SampleService){
  
  }

}

To learn more about Angular Dependency Injection, check out the Official Angular Documentation.

Preview your library during development

To preview your library code during development, start the playground:

$ npm run playground

Changes to your library code will be updated live in the browser window:

playground

Consuming your library in a local application during development

To consume your library in a local application before you publish it to npm, you can follow the following steps:

Create your library:
```
$ yo angular2-library
```
Let's assume you name your library sample-library.
Navigate to the sample-library directory:
```
$ cd sample-library
```
Compile your library files:
```
$ npm run build
```
From the sample-library/dist directory, create a symlink in the global node_modules directory to the dist directory of your library:
```
$ cd dist
$ npm link
```
Create a new Angular app. Let's assume you use angular-cli:
```
$ cd /your-projects-path
$ ng new my-app
```
Navigate to the my-app directory:
```
$ cd my-app
```
From the my-app directory, link the global sample-library directory to node_modules of the my-app directory:
```
$ npm link sample-library
```

Import SampleModule in your Angular application:

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppComponent } from './app.component';

// Import your library
import { SampleModule } from 'sample-library';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    
    // Specify your library as an import
    SampleModule.forRoot()
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Once your shared library is imported, you can use its components, directives and pipes in your Angular application templates:

<!-- app.component.html -->
<h1>{{ title }}</h1>
<sample-component>
  This component is part of the shared library and will now work as expected.
</sample-component>

and if you need to access a service from your shared library, you can inject it using Dependency Injection:

import { Component } from '@angular/core';

// Import the shared service
import { SampleService } from 'sample-library';

@Component({
  template: 'Injecting a service from the shared library'
})
export class HomeComponent {

  // Inject the service using Angular DI 
  constructor(private sampleService: SampleService){
  
  }

}

When you make a change to your library, recompile your library files again from your sample-library directory:
```
$ npm run build
```
If you want to automatically recompile the library files when a file in src changes, run
```
$ npm run build:watch
```

If you are using an Angular CLI application to consume your library, make sure to set up a path mapping in /src/tsconfig.app.json of your consuming application (not your library):

{
  "compilerOptions": {
    // ...
    // Note: these paths are relative to `baseUrl` path.
    "paths": {
      "@angular/*": [
        "../node_modules/@angular/*"
      ]
    }
  }
}

When you npm link a library with peer dependencies, the consuming application searches for the peer dependencies in the library's parent directories instead of the application's parent directories.

If you get Error: Unexpected value '[object Object]' imported by the module 'AppModule'. Please add a @NgModule annotation., then try:

$ ng serve --preserve-symlinks

to make sure the consuming application searches for the peer dependencies in the application's node_modules directory.

Frequently asked questions

How can I configure Karma?

Currently, the generator does not create a custom Karma configuration for running unit tests.

If your library requires a custom Karma setup, please check out this tutorial on how to configure Karma for your library (Credits to Raphael).

As soon as official recommendations are available on how to set up Karma for testing libraries, this generator will be updated accordingly.

How can I use a scoped package name?

First update the package name in src/package.json:

"name": "@scope/library-name"

and then also update flatModuleId in src/tsconfig.es5.json accordingly:

"flatModuleId": "@scope/library-name"

See #75 for more information.

How can I avoid recompilation during development

If you experience issues (#72) or want to avoid constant recompilation of your library during development, you can also npm link src instead of npm link dist in step 4 of the process above.

This will let you consume the TypeScript code directly from the src directory of your library instead of the generated bundle from the dist directory. This increases development speed if you are testing your library in a local Angular application, but remember to test the generated bundle using npm link dist after you finish writing your code, to ensure that your generated bundle is working as expected before you publish your library to NPM.

How can I use .scss files?

Simply store your styles in a file with a filename extension of scss and reference it in your component's styleUrls property.

So if you have a sample.component.scss:

h1 {
  color: red;
}

then reference it in your component's styleUrls in sample.component.ts accordingly:

@Component({
  selector: 'sample-component',
  template: `<h1>Sample component</h1>`,
  styleUrls: [
    'sample.component.scss'
  ]
})

The .scss files will automatically be compiled and inlined in your library bundle.

How can I import .scss files

To import a .scss file in an existing .scss file, you can specify a relative path:

@import '../relative/path/to/other.scss';

or use a tilde to import a file from the nearest parent node_modules directory:

@import '~@angular/material/prebuilt-themes/deeppurple-amber.css';

How can I see which version of the generator I have installed

From the command line, run:

$ npm ls -g --depth=1 2>/dev/null | grep generator-

How can I update my generator to the latest version?

From the command line, run

$ yo

and select the option Update your generators.

What if my library depends on a third party library?

If your library depends on a third party library such as Angular Material or PrimeNG, you don't have to include the third party library in your library.

Instead, you should add the third party library as a peer dependency to the peerDependencies property in src/package.json of your library:

"peerDependencies": {
  "@angular/core": "^4.0.0",
  "rxjs": "^5.1.0",
  "zone.js": "^0.8.4"
}

This causes a warning to be displayed when the consuming application runs npm install and does not have the third party library installed that your library depends on.

The generator already adds @angular/core, rxjs and zone.js as peer dependencies for you by default.

Consider the following scenario where your library depends on a third party library called "PrimeNG".

In your Angular library:

run npm install primeng --save to install PrimeNG and add it as a devDependency to package.json in the root directory
add PrimeNG as a peerDependency in src/package.json, NOT as dependency or devDependency (src/package.json is the package.json that is distributed with your library, so you must specify primeng as peer dependency here, NOT in the package.json file in the root of your library)
import the necessary PrimeNG Angular module(s) in your library Angular module
write code that uses PrimeNG components
build your library and publish it (or link it locally)

In the consuming Angular application

run npm install yourlibrary to install your library (which should display a warning if PrimeNG is not installed) or link it locally
run npm install primeng to install PrimeNG if it is not installed yet
import the necessary PrimeNG Angular module(s) in your Angular application module (usually AppModule) (this step is not needed if your library exports the PrimeNG module(s) in its module metadata)
import your library module in your Angular application module (usually AppModule)
you can now use your library components

To see a fully documented example, check out this guide.

How can I upgrade my library to support Angular 5

Version 12 or later of this generator supports Angular 5.

If you have an existing library that was generated with an earlier version of this generator:

update the versions of the Angular packages in package.json to Angular 5 (example)
replace the ngc script in your gulpfile.js with:

gulp.task('ngc', function () {
  ngc([ '--project', `${tmpFolder}/tsconfig.es5.json` ]);
  return Promise.resolve()
});

See #230 for more information.

Issues

Please report bugs and issues here.

Development

To run the generator unit tests:

$ npm run test

License

MIT © Jurgen Van de Moere

Change log

v12.4.0

Fix tslint rule #286 (Credits to Mathias Wittlock)

v12.4.1

Fix tslint rule #286 (Credits to Mathias Wittlock)

v12.4.0

Add prompt to ask for scope #283 (Credits to Fabrizio Fortunato)

v12.3.0

Update rollup options #270 (Credits to Zura Gabievi)
Fix mkdir error #269 (Credits to Louis Amstutz)

v12.2.1

Update system.js config to use single quotes

v12.2.0

Added default extension to playground system.js config to fix #146

v12.1.0

Fixed issue with deleting .tmp folder after failed build (See #261) (Credits to Fabrizio Fortunato)
Updated package_jest.json (See #267) (Credits to Fabrizio Fortunato)