ngx-build-plus

Extend the Angular CLI's default build behavior without ejecting:

• Extend the default behavior by providing a partial config that just contains your additional settings
• Alternative: Extend the default behavior by providing a custom function
• Optional: Build a single bundle (e. g. for Angular Elements)
• Inherits from the default builder, hence you have the same options
• Provides schematics for some advanced use cases like webpack externals
• Simple to use
• No eject needed

Credits

Big thanks to Rob Wormald and David Herges!

Get the right version

• Angular 6-7/ CLI 6-7: [email protected]^7
• Angular 8/ CLI 8: ngx-build-plus^8.0.0
• Angular 9/ CLI 9: ngx-build-plus^9.0.0

Updating to Version 8

ng update ngx-build-plus --force

Breaking Changes

Version 7

• The switch single-bundle now defaults to false to align with the CLI's default behavior.

Version 9

• keepPolyfills and keepStyles default to true to avoid misunderstandings.

Schematics and Options

Options

• ng build --single-bundle: Puts everything reachable from the main entry point into one bundle. Polyfills, scripts, and styles stay in their own bundles as the consuming application might have its own versions of these.

Schematics

• ng add ngx-build-plus
• ng g ngx-build-plus:wc-polyfill: Adds webcomponent polyfills to your app
• ng g ngx-build-plus:externals: Updates your app to use webpack externals (see example at the end)

Getting started

This shows a minimal example for getting started. It uses a minimal partial webpack configuration that is merged into the CLI's one. Representative for all possible custom webpack configurations, the used one just leverages the DefinePlugin to create a global VERSION constant during the build.

Please find the example shown here in the sample application in the folder projects/getting-started.

1. Create a new Angular project with the CLI

2. Add ngx-build-plus: ng add ngx-build-plus

   Note: If you want to add it to specific sub project in your projects folder, use the --project switch to point to it: ng add ngx-build-plus --project getting-started

   Remark: This step installs the package via npm and updates your angular.json so that your project uses custom builders for ng serve and ng build.

3. Add a file webpack.partial.js to the root of your (sub-)project:

   const webpack = require('webpack');
   
   module.exports = {
       plugins: [
           new webpack.DefinePlugin({
               "VERSION": JSON.stringify("4711")
           })
       ]
   }
   

4. Use the global variable VERSION in your app.component.ts:

   import { Component } from '@angular/core';
   
   declare const VERSION: string;
   
   @Component({
       selector: 'app-root',
       templateUrl: './app.component.html',
       styleUrls: ['./app.component.css']
   })
   export class AppComponent {
       title = 'Version: ' + VERSION;
   }
   

5. Start your application with the --extra-webpack-config switch pointing to your partial webpack config:

   ng serve --extra-webpack-config webpack.partial.js -o
   

   If your project is a CLI based sub project, use the --project switch too:

   ng serve --project getting-started -o --extra-webpack-config webpack.partial.js
   

   Hint: Consider creating a npm script for this command.

6. Make sure that the VERSION provided by your webpack config is displayed.

ngx-build-plus and Angular Elements

While ngx-build-plus can be used in every Angular configuration, it also comes with some schematics automating some scenarios for Angular Elements. More information about can be found here.

Using Plugins

Plugins allow you to provide some custom code that modifies your webpack configuration. In addition to that, they also provide a pre- and a post-hook for tasks that need to take happen before and after bundling. This is an example for an plugin:

export default {
    pre(options) {
        console.debug('pre');
    },
    config(cfg) {
        console.debug('config');
        return cfg;
    },
    post(options) {
        console.debug('post');
    }
}

As this plugin is written with TypeScript you need to compile it.

The config method works like a configHook (see above).

To use a plugin, point to it's JavaScript representation (not the TypeScript file) using the --plugin switch:

ng build --plugin ~dist\out-tsc\hook\plugin

The prefix ~ points to the current directory. Without this prefix, ngx-build-plus assumes that the plugin is an installed node_module.

Using different merging strategies

You can also use plugins to implement different merging strategies. The following plugin demonstrates this:

var merge = require('webpack-merge');
var webpack = require('webpack');

exports.default = {
    config: function(cfg) {
        const strategy = merge.strategy({
            'plugins': 'prepend'
        });

        return strategy (cfg, {
            plugins: [
                new webpack.DefinePlugin({
                    "VERSION": JSON.stringify("4711")
                })
            ]
        });
    }
}

To execute this, use the following command:

ng build --plugin ~my-plugin.js

One more time, the ~ tells ngx-build-plus that the plugin is not an installed node_module but a local file.

Advanced example: Externals and Angular Elements

This shows another example for using ngx-build-plus. It uses a custom webpack configuration to define some dependencies of an Angular Element as external which can be loaded separately into the browser and shared among several bundles.

If you are not interested into this very use case, skip this section.

The result of this description can be found in the repository's sample directory.

1. Create a new Angular CLI based project and install @angular/elements as well as @webcomponents/custom-elements which provides needed polyfills:

   npm i @angular/elements --save
   

2. Expose a component as an Custom Element:

   import { BrowserModule } from '@angular/platform-browser';
   import { NgModule, Injector } from '@angular/core';
   import { createCustomElement } from '@angular/elements';
   
   import { AppComponent } from './app.component';
   
   @NgModule({
       imports: [
           BrowserModule
       ],
       declarations: [
           AppComponent
       ],
       providers: [],
       bootstrap: [],
       entryComponents:[AppComponent]
   })
   export class AppModule { 
   
       constructor(private injector: Injector) {
       }
   
       ngDoBootstrap() {
           const elm = createCustomElement(AppComponent, { injector: this.injector });
           customElements.define('custom-element', elm);
       }
   
   }
   

3. Install ngx-build-plus:

   When using Angular >= 7 and CLI >= 7, you can simply use ng add for installing ngx-build-plus:

   ng add ngx-build-plus 
   

   If you are using a monorepo, mention the project you want to install ngx-build-plus for:

   ng add ngx-build-plus --project myProject
   

4. Add polyfills:

   ng g ngx-build-plus:wc-polyfill --project myProject
   

5. Execute the externals schematic:

   ng g ngx-build-plus:externals --project myProject
   

6. This creates a partial webpack config in your project's root:

   module.exports = {
       "externals": {
           "rxjs": "rxjs",
           "@angular/core": "ng.core",
           "@angular/common": "ng.common",
           "@angular/platform-browser": "ng.platformBrowser",
           "@angular/elements": "ng.elements"
       }
   }
   

7. Build your application. You can use the npm script created by the above mentioned schematic:

   npm run build:myProject:externals
   

8. Angular will now be compiled into a scripts.js and can be reused amongs several seperately compiled bundles. Your code is in the main bundle which is quite tiny b/c it does not contain Angular.

Further information about this can be found in my blog here.

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