A Gentle Introduction to Angular Schematics - Angular SF 2019

A Gentle Introduction to Angular Schematics
June 13, 2019
Matt Raible | @mraible
Photo by Joseph Barrientos unsplash.com/photos/Ji_G7Bu1MoM

Blogger on raibledesigns.com and

developer.okta.com/blog
Web Developer and Java Champion
Father, Husband, Skier, Mountain
Biker, Whitewater Rafter
Open Source Connoisseur
Hi, I’m Matt Raible!
Bus Lover
Okta Developer Advocate

Agenda
1. What are Angular Schematics?
2. Create and Test a Schematic
3. Schematic Templates
4. Template Expression Language
5. OpenID Connect Authentication
6. Schematics for React, Vue, and Ionic

Create a Schematic
$ npm i -g @angular-devkit/schematics-cli
$ schematics blank —-name=my-component
CREATE /my-component/README.md (639 bytes)
CREATE /my-component/.gitignore (191 bytes)
CREATE /my-component/.npmignore (64 bytes)
CREATE /my-component/package.json (539 bytes)
CREATE /my-component/tsconfig.json (656 bytes)
CREATE /my-component/src/collection.json (231 bytes)
CREATE /my-component/src/my-component/index.ts (318 bytes)
CREATE /my-component/src/my-component/index_spec.ts (474 bytes)

Project metadata: collection.json
{
"$schema": "../node_modules/@angular-devkit/schematics/collection-schema.json",
"schematics": {
"my-component": {
"description": "A blank schematic.",
"factory": "./my-component/index#myComponent"
}
}

Factory function: index.ts
import { Rule, SchematicContext, Tree } from '@angular-devkit/schematics';
export function myComponent(_options: any): Rule {
return (tree: Tree, _context: SchematicContext) => {
return tree;
};
}

Unit test: index_spec.ts
import { Tree } from '@angular-devkit/schematics';
import { SchematicTestRunner } from '@angular-devkit/schematics/testing';
import * as path from 'path';
const collectionPath = path.join(__dirname, '../collection.json');
describe('my-component', () => {
it('works', () => {
const runner = new SchematicTestRunner('schematics', collectionPath);
const tree = runner.runSchematic('my-component', {}, Tree.empty());
expect(tree.files).toEqual([]);
});
});

Copy and Manipulate Templates: directory structure
$ tree .
src/my-component/
├── files
│ └── src
│ └── app
│ ├── app.component.html
│ └── app.component.ts
├── index.ts
└── index_spec.ts

Copy and Manipulate Templates: app.component.ts
import { Component } from '@angular/core';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent {
name = '<%= name %>';
}
src/my-component/files/src/app/app.component.ts

Copy and Manipulate Templates: app.component.html
src/my-component/files/src/app/app.component.html
<div style="text-align:center">
<h1>
Hello, {{ name }}
</h1>
</div>
<router-outlet></router-outlet>

Copy and Manipulate Templates: schema.json
{
"$schema": "http://json-schema.org/schema",
"id": "SchematicsMyComponent",
"title": "My Component Schema",
"type": "object",
"properties": {
"name": {
"type": "string",
"description": "Your Name",
"x-prompt": "What is your name?"
}
},
"required": ["name"]
}

Copy and Manipulate Templates: collection.json
{
"schematics": {
"my-component": {
"factory": "./my-component/index#myComponent",
"schema": "./my-component/schema.json"
}
}
}

Copy and Manipulate Templates: index.ts
export function myComponent(_options: any): Rule {
return (tree: Tree, _context: SchematicContext) => {
setupOptions(tree, _options);
const movePath = normalize(_options.path + '/');
const templateSource = apply(url('./files/src'), [
template({..._options}),
move(movePath),
// fix for https://github.com/angular/angular-cli/issues/11337
forEach((fileEntry: FileEntry) => {
if (tree.exists(fileEntry.path)) {
tree.overwrite(fileEntry.path, fileEntry.content);
}
return fileEntry;
}),
]);
const rule = mergeWith(templateSource, MergeStrategy.Overwrite);
return rule(tree, _context);
};
}

Copy and Manipulate Templates: setupOptions()
export function setupOptions(host: Tree, options: any): Tree {
const workspace = getWorkspace(host);
if (!options.project) {
options.project = Object.keys(workspace.projects)[0];
}
const project = workspace.projects[options.project];
options.path = join(normalize(project.root), 'src');
return host;
}

Copy and Manipulate Templates: index_spec.ts
beforeEach(() => {
appTree = schematicRunner.runExternalSchematic(
'@schematics/angular', 'workspace', workspaceOptions);
appTree = schematicRunner.runExternalSchematic(
'@schematics/angular', 'application', appOptions, appTree);
});
it('works', () => {
const runner = new SchematicTestRunner('schematics', collectionPath);
runner.runSchematicAsync(
'my-component', schemaOptions, appTree).toPromise().then(tree => {
const appComponent = tree.readContent(
‘/projects/schematest/src/app/app.component.ts');
expect(appComponent).toContain(`name = '${schemaOptions.name}'`);
});
});

Run Your Schematic with Angular CLI
$ npm pack
$ ng new my-test-app --routing --style css
$ cd my-test-app
$ npm install ../my-component/my-component-0.0.0.tgz
$ ng g my-component:my-component

Publish Your Schematic to npm
!22
By default, .npmignore ignores all TypeScript files
Modify .npmignore so it doesn't exclude your template files!
Run npm publish

Add Support for ng add with Angular CLI
!23
{
"schematics": {
"my-component": {
"factory": "./my-component/index#myComponent",
},
"ng-add": {
"factory": "./ng-add/index",
"description": "Add schematic",
}
}
}

Add Support for ng add with Angular CLI
!24
import { chain, Rule, schematic, SchematicContext, Tree, }
from '@angular-devkit/schematics';
export default function (options: any): Rule {
return (host: Tree, context: SchematicContext) => {
return chain([
schematic('my-component', options)
])(host, context);
};
}

Template Expression Language
Placeholder Description
<%= expression %>
Replaced with the result of the call of the given expression. This only supports
direct expressions, no structural (for/if/...) JavaScript.
<%- expression %>
Same as above, but the value of the result will be escaped for HTML when
inserted (i.e. replacing '<' with '<')
<% inline code %>
Inserts the given code into the template structure, allowing to insert structural
JavaScript.
<%# text %> A comment, which gets entirely dropped.
https://www.npmjs.com/package/@angular-devkit/schematics#content-templating

Example Template Code
import { Injectable } from '@angular/core';
<% if (platform === 'cordova') { %>
import { CordovaBrowser } from ‘ionic-appauth/lib/cordova';
<% } else { %>
import { CapacitorBrowser } from ‘ionic-appauth/lib/capacitor';
<% } %>
@Injectable({
providedIn: 'root'
})
export class BrowserService extends
<%= (platform === 'cordova') ? 'CordovaBrowser' : 'CapacitorBrowser' %> {
}

Secure Your Angular App in Minutes!
$ ng new my-secure-app --routing
$ cd my-secure-app
// create a SPA app on Okta, copy settings
$ ng add @oktadev/schematics

git clone https://github.com/oktadeveloper/okta-spring-webflux-react-
example.git
Blog, Screencast, and Source Code
https://developer.okta.com/blog/2019/02/13/angular-schematics

Thanks!
Keep in Touch
raibledesigns.com
@mraible
Presentations
speakerdeck.com/mraible
Code
github.com/oktadeveloper
developer.okta.com

A Gentle Introduction to Angular Schematics - Angular SF 2019

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