docs(core): in template syntax guide, make SVG example more clear (#31356)

add e2e test for SVG template example
fix template syntax example app
- linting errors
- runtime exceptions
- template type errors
- deprecated type casting
- deprecated currency pipe example

Relates to #30559

PR Close #31356

aio/content/examples/template-syntax/src/app/app.component.html

@@ -38,6 +38,7 @@
 <a href="#safe-navigation-operator">Safe navigation operator <i>?.</i></a><br>
 <a href="#non-null-assertion-operator">Non-null assertion operator <i>!.</i></a><br>
 <a href="#enums">Enums</a><br>
+<a href="#svg-templates">SVG Templates</a><br>
 
 <!-- Interpolation and expressions -->
 <hr><h2 id="interpolation">Interpolation</h2>
@@ -442,7 +443,7 @@ button</button>
 
 <!-- #docregion without-NgModel -->
 <input [value]="currentHero.name"
-       (input)="currentHero.name=$event.target.value" >
+       (input)="updateCurrentHeroName($event)">
 <!-- #enddocregion without-NgModel -->
 without NgModel
 <br>
@@ -752,7 +753,7 @@ bindon-ngModel
 
 <div>
   <!-- pipe price to USD and display the $ symbol -->
-  <label>Price: </label>{{product.price | currency:'USD':true}}
+  <label>Price: </label>{{product.price | currency:'USD':'symbol'}}
 </div>
 
 <a class="to-toc" href="#toc">top</a>
@@ -857,3 +858,9 @@ The null hero's name is {{nullHero && nullHero.name}}
 </p>
 
 <a class="to-toc" href="#toc">top</a>
+
+<hr><h2 id="svg-templates">SVG Templates</h2>
+<!-- #docregion svg-templates -->
+<app-svg></app-svg>
+<!-- #enddocregion svg-templates -->
+<a class="to-toc" href="#toc">top</a>

aio/content/examples/template-syntax/src/app/app.component.ts

@@ -5,7 +5,7 @@ import { AfterViewInit, Component, ElementRef, OnInit, QueryList, ViewChildren }
 
 import { Hero } from './hero';
 
-export enum Color {Red, Green, Blue};
+export enum Color {Red, Green, Blue}
 
 /**
  * Giant grab bag of stuff to drive the chapter
@@ -29,7 +29,7 @@ export class AppComponent implements AfterViewInit, OnInit {
     trackChanges(this.heroesWithTrackBy, () => this.heroesWithTrackByCount++);
   }
 
-  @ViewChildren('noTrackBy')   heroesNoTrackBy:   QueryList<ElementRef>;
+  @ViewChildren('noTrackBy')   heroesNoTrackBy: QueryList<ElementRef>;
   @ViewChildren('withTrackBy') heroesWithTrackBy: QueryList<ElementRef>;
 
   actionName = 'Go for it';
@@ -66,6 +66,10 @@ export class AppComponent implements AfterViewInit, OnInit {
 
   currentHero: Hero;
 
+  updateCurrentHeroName(event: Event) {
+    this.currentHero.name = (event.target as any).value;
+  }
+
   deleteHero(hero?: Hero) {
     this.alert(`Delete ${hero ? hero.name : 'the hero'}.`);
   }
@@ -105,13 +109,13 @@ export class AppComponent implements AfterViewInit, OnInit {
 
   get nullHero(): Hero { return null; }
 
-  onClickMe(event?: KeyboardEvent) {
-    let evtMsg = event ? ' Event target class is ' + (<HTMLElement>event.target).className  : '';
+  onClickMe(event?: MouseEvent) {
+    const evtMsg = event ? ' Event target class is ' + (event.target as HTMLElement).className  : '';
     this.alert('Click me.' + evtMsg);
   }
 
-  onSave(event?: KeyboardEvent) {
-    let evtMsg = event ? ' Event target is ' + (<HTMLElement>event.target).textContent : '';
+  onSave(event?: MouseEvent) {
+    const evtMsg = event ? ' Event target is ' + (event.target as HTMLElement).textContent : '';
     this.alert('Saved.' + evtMsg);
     if (event) { event.stopPropagation(); }
   }
@@ -140,9 +144,9 @@ export class AppComponent implements AfterViewInit, OnInit {
   setCurrentClasses() {
     // CSS classes: added/removed per current state of component properties
     this.currentClasses =  {
-      'saveable': this.canSave,
-      'modified': !this.isUnchanged,
-      'special':  this.isSpecial
+      saveable: this.canSave,
+      modified: !this.isUnchanged,
+      special:  this.isSpecial
     };
   }
   // #enddocregion setClasses
@@ -164,7 +168,7 @@ export class AppComponent implements AfterViewInit, OnInit {
   // #enddocregion trackByHeroes
 
   // #docregion trackById
-  trackById(index: number, item: any): number { return item['id']; }
+  trackById(index: number, item: any): number { return item.id; }
   // #enddocregion trackById
 }
 

aio/content/examples/template-syntax/src/app/app.module.ts

@@ -1,14 +1,14 @@
-import { NgModule }       from '@angular/core';
-import { BrowserModule }  from '@angular/platform-browser';
-import { FormsModule }    from '@angular/forms';
+import { NgModule } from '@angular/core';
+import { BrowserModule } from '@angular/platform-browser';
+import { FormsModule } from '@angular/forms';
 
 import { AppComponent } from './app.component';
 import { BigHeroDetailComponent, HeroDetailComponent } from './hero-detail.component';
 import { ClickDirective, ClickDirective2 } from './click.directive';
-import { HeroFormComponent }      from './hero-form.component';
-import { heroSwitchComponents }   from './hero-switch.components';
-import { SizerComponent }         from './sizer.component';
-import { SvgComponent }           from './svg.component';
+import { HeroFormComponent } from './hero-form.component';
+import { heroSwitchComponents } from './hero-switch.components';
+import { SizerComponent } from './sizer.component';
+import { SvgComponent } from './svg.component';
 
 @NgModule({
   imports: [

aio/content/examples/template-syntax/src/app/click.directive.ts

@@ -1,4 +1,4 @@
-/* tslint:disable use-output-property-decorator directive-class-suffix */
+/* tslint:disable directive-selector directive-class-suffix */
 // #docplaster
 import { Directive, ElementRef, EventEmitter, Output } from '@angular/core';
 

aio/content/examples/template-syntax/src/app/hero-form.component.ts

@@ -1,5 +1,5 @@
 import { Component, Input, ViewChild } from '@angular/core';
-import { NgForm }                      from '@angular/forms';
+import { NgForm } from '@angular/forms';
 
 import { Hero } from './hero';
 
@@ -15,10 +15,11 @@ export class HeroFormComponent {
   @Input() hero: Hero;
   @ViewChild('heroForm', {static: false}) form: NgForm;
 
+  // tslint:disable-next-line:variable-name
   private _submitMessage = '';
 
   get submitMessage() {
-    if (!this.form.valid) {
+    if (this.form && !this.form.valid) {
       this._submitMessage = '';
     }
     return this._submitMessage;

aio/content/examples/template-syntax/src/app/svg.component.svg

@@ -1,6 +1,6 @@
 <svg>
   <g>
-    <rect x="0" y="0" width="100" height="100" [attr.fill]="fill" (click)="changeColor()" />
+    <rect x="0" y="0" width="100" height="100" [attr.fill]="fillColor" (click)="changeColor()" />
     <text x="120" y="50">click the rectangle to change the fill color</text>
   </g>
 </svg>

aio/content/examples/template-syntax/src/app/svg.component.ts

@@ -6,12 +6,12 @@ import { Component } from '@angular/core';
   styleUrls: ['./svg.component.css']
 })
 export class SvgComponent {
-  fill = 'rgb(255, 0, 0)';
+  fillColor = 'rgb(255, 0, 0)';
 
   changeColor() {
     const r = Math.floor(Math.random() * 256);
     const g = Math.floor(Math.random() * 256);
     const b = Math.floor(Math.random() * 256);
-    this.fill = `rgb(${r}, ${g}, ${b})`;
+    this.fillColor = `rgb(${r}, ${g}, ${b})`;
   }
 }