Reactivity
Declare state
Angular Renaissance
import { Component, signal } from "@angular/core";
@Component({
selector: "app-name",
template: `<h1>Hello {{ name() }}</h1>`,
})
export class NameComponent {
name = signal("John");
}
Ember Polaris
import Component from "@glimmer/component";
export default class NameComponent extends Component {
name = "John";
<template>
<h1>Hello {{this.name}}</h1>
</template>
}
Update state
Angular Renaissance
import { Component, signal } from "@angular/core";
@Component({
selector: "app-name",
template: `<h1>Hello {{ name() }}</h1>`,
})
export class NameComponent {
name = signal("John");
constructor() {
this.name.set("Jane");
}
}
Ember Polaris
import Component from "@glimmer/component";
import { tracked } from "@glimmer/tracking";
export default class CounterComponent extends Component {
@tracked name = "John";
constructor(owner, args) {
super(owner, args);
this.name = "Jane";
}
<template>
<h1>Hello {{this.name}}</h1>
</template>
}
Computed state
Angular Renaissance
import { Component, computed, signal } from "@angular/core";
@Component({
selector: "app-double-count",
template: `<div>{{ doubleCount() }}</div>`,
})
export class DoubleCountComponent {
count = signal(10);
doubleCount = computed(() => this.count() * 2);
}
Ember Polaris
import Component, { tracked } from "@glimmer/component";
export default class DoubleCount extends Component {
@tracked count = 10;
get doubleCount() {
return this.count * 2;
}
<template>
<div>{{this.doubleCount}}</div>
</template>
}
Templating
Minimal template
Angular Renaissance
import { Component } from "@angular/core";
@Component({
selector: "app-hello-world",
template: `<h1>Hello world</h1>`,
})
export class HelloWorldComponent {}
Ember Polaris
<template>
<h1>Hello world</h1>
</template>Styling
Angular Renaissance
import { Component } from "@angular/core";
@Component({
selector: "app-css-style",
template: `
<h1 class="title">I am red</h1>
<button style="font-size: 10rem">I am a button</button>
`,
styles: `
.title {
color: red;
}
`,
})
export class CssStyleComponent {}
Ember Polaris
<template>
<h1 class="title">I am red</h1>
<button style="font-size: 10rem;">I am a button</button>
<style>
.title {
color: red;
}
</style>
</template>Loop
Angular Renaissance
import { Component } from "@angular/core";
@Component({
selector: "app-colors",
template: `
<ul>
@for (color of colors; track color) {
<li>{{ color }}</li>
}
</ul>
`,
})
export class ColorsComponent {
colors = ["red", "green", "blue"];
}
Ember Polaris
const colors = ["red", "green", "blue"];
<template>
<ul>
{{#each colors as |color|}}
<li>{{color}}</li>
{{/each}}
</ul>
</template>Event click
Angular Renaissance
import { Component, signal } from "@angular/core";
@Component({
selector: "app-counter",
template: `
<p>Counter: {{ count() }}</p>
<button (click)="incrementCount()">+1</button>
`,
})
export class CounterComponent {
count = signal(0);
incrementCount() {
this.count.update((count) => count + 1);
}
}
Ember Polaris
import Component from "@glimmer/component";
import { tracked } from "@glimmer/tracking";
export default class Counter extends Component {
@tracked count = 0;
incrementCount = () => this.count++;
<template>
<p>Counter: {{this.count}}</p>
<button {{on "click" this.incrementCount}}>+1</button>
</template>
}
Dom ref
Angular Renaissance
import {
afterNextRender,
Component,
ElementRef,
viewChild,
} from "@angular/core";
@Component({
selector: "app-input-focused",
template: `<input type="text" #inputRef />`,
})
export class InputFocusedComponent {
inputRef = viewChild.required<ElementRef<HTMLInputElement>>("inputRef");
constructor() {
afterNextRender({ write: () => this.inputRef().nativeElement.focus() });
}
}
Ember Polaris
import { modifier } from "ember-modifier";
const autofocus = modifier((element) => element.focus());
<template>
<input {{autofocus}} />
</template>Conditional
Angular Renaissance
import { Component, computed, signal } from "@angular/core";
const TRAFFIC_LIGHTS = ["red", "orange", "green"];
@Component({
selector: "app-traffic-light",
template: `
<button (click)="nextLight()">Next light</button>
<p>Light is: {{ light() }}</p>
<p>
You must
@switch (light()) {
@case ("red") {
<span>STOP</span>
}
@case ("orange") {
<span>SLOW DOWN</span>
}
@case ("green") {
<span>GO</span>
}
}
</p>
`,
})
export class TrafficLightComponent {
lightIndex = signal(0);
light = computed(() => TRAFFIC_LIGHTS[this.lightIndex()]);
nextLight() {
this.lightIndex.update((index) => (index + 1) % TRAFFIC_LIGHTS.length);
}
}
Ember Polaris
import Component from "@glimmer/component";
import { tracked } from "@glimmer/tracking";
const TRAFFIC_LIGHTS = ["red", "orange", "green"];
export default class TrafficLight extends Component {
@tracked lightIndex = 0;
get light() {
return TRAFFIC_LIGHTS[this.lightIndex];
}
nextLight = () => {
this.lightIndex = (this.lightIndex + 1) % TRAFFIC_LIGHTS.length;
};
<template>
<button {{on "click" this.nextLight}}>Next light</button>
<p>Light is: {{this.light}}</p>
<p>
You must
{{#if (eq this.light "red")}}
STOP
{{else if (eq this.light "orange")}}
SLOW DOWN
{{else if (eq this.light "green")}}
GO
{{/if}}
</p>
</template>
}
Lifecycle
On mount
Angular Renaissance
import { Component, OnInit, signal } from "@angular/core";
@Component({
selector: "app-page-title",
template: `<p>Page title: {{ pageTitle() }}</p>`,
})
export class PageTitleComponent implements OnInit {
pageTitle = signal("");
ngOnInit() {
this.pageTitle.set(document.title);
}
}
Ember Polaris
const pageTitle = () => document.title;
<template>
<p>Page title is: {{(pageTitle)}}</p>
</template>
On unmount
Angular Renaissance
import { Component, OnDestroy, signal } from "@angular/core";
@Component({
selector: "app-time",
template: `<p>Current time: {{ time() }}</p>`,
})
export class TimeComponent implements OnDestroy {
time = signal(new Date().toLocaleTimeString());
timer = setInterval(
() => this.time.set(new Date().toLocaleTimeString()),
1000,
);
ngOnDestroy() {
clearInterval(this.timer);
}
}
Ember Polaris
import Component from "@glimmer/component";
import { tracked } from "@glimmer/tracking";
import { registerDestructor } from "@ember/destroyable";
export default class Time extends Component {
@tracked time = new Date().toLocaleTimeString();
constructor(owner, args) {
super(owner, args);
let timer = setInterval(() => {
this.time = new Date().toLocaleTimeString();
}, 1000);
registerDestructor(this, () => clearInterval(timer));
}
<template>
<p>Current time: {{this.time}}</p>
</template>
}
Component composition
Props
Angular Renaissance
import { Component } from "@angular/core";
import { UserprofileComponent } from "./userprofile.component";
@Component({
selector: "app-root",
imports: [UserprofileComponent],
template: `
<app-userprofile
name="John"
[age]="20"
[favouriteColors]="['green', 'blue', 'red']"
[isAvailable]="true"
/>
`,
})
export class AppComponent {}
Ember Polaris
import UserProfile from "./user-profile.gjs";
const favoriteColors = ["green", "blue", "red"];
<template>
<UserProfile
@name="John"
@age={{20}}
@favouriteColors={{favoriteColors}}
@isAvailable={{true}}
/>
</template>Emit to parent
Angular Renaissance
import { Component, signal } from "@angular/core";
import { AnswerButtonComponent } from "./answer-button.component";
@Component({
selector: "app-root",
imports: [AnswerButtonComponent],
template: `
<p>Are you happy?</p>
<app-answer-button (yes)="onAnswerYes()" (no)="onAnswerNo()" />
<p style="font-size: 50px">{{ isHappy() ? "😀" : "😥" }}</p>
`,
})
export class AppComponent {
isHappy = signal(true);
onAnswerYes() {
this.isHappy.set(true);
}
onAnswerNo() {
this.isHappy.set(false);
}
}
Ember Polaris
<template>
<button {{on "click" @onYes}}> YES </button>
<button {{on "click" @onNo}}> NO </button>
</template>
Slot
Angular Renaissance
import { Component } from "@angular/core";
import { FunnyButtonComponent } from "./funny-button.component";
@Component({
selector: "app-root",
imports: [FunnyButtonComponent],
template: `<app-funny-button>Click me!</app-funny-button>`,
})
export class AppComponent {}
Ember Polaris
import FunnyButton from "./funny-button";
<template>
<FunnyButton>Click me!</FunnyButton>
</template>
Slot fallback
Angular Renaissance
import { Component } from "@angular/core";
import { FunnyButtonComponent } from "./funny-button.component";
@Component({
selector: "app-root",
imports: [FunnyButtonComponent],
template: `
<app-funny-button />
<app-funny-button>I got content!</app-funny-button>
`,
})
export class AppComponent {}
Ember Polaris
import FunnyButton from "./funny-button";
<template>
<FunnyButton />
<FunnyButton>I got content!</FunnyButton>
</template>Context
Angular Renaissance
import { Component, inject } from "@angular/core";
import { UserService } from "./user.service";
import { UserProfileComponent } from "./user-profile.component";
@Component({
imports: [UserProfileComponent],
providers: [UserService],
selector: "app-root",
template: `
<h1>Welcome back, {{ userService.user().username }}</h1>
<app-user-profile />
`,
})
export class AppComponent {
protected userService = inject(UserService);
}
Ember Polaris
import UserProfile from "./user-profile";
<template>
<UserProfile />
</template>
Form input
Input text
Angular Renaissance
import { Component, signal } from "@angular/core";
import { FormsModule } from "@angular/forms";
@Component({
imports: [FormsModule],
selector: "app-input-hello",
template: `
<p>{{ text() }}</p>
<input [(ngModel)]="text" />
`,
})
export class InputHelloComponent {
text = signal("");
}
Ember Polaris
import Component from "@glimmer/component";
import { tracked } from "@glimmer/tracking";
export default class InputHello extends Component {
@tracked text = "Hello World";
handleInput = (event) => (this.text = event.target.value);
<template>
<p>{{this.text}}</p>
<input value={{this.text}} {{on "input" this.handleInput}} />
</template>
}
Checkbox
Angular Renaissance
import { Component, signal } from "@angular/core";
import { FormsModule } from "@angular/forms";
@Component({
imports: [FormsModule],
selector: "app-is-available",
template: `
<input id="is-available" type="checkbox" [(ngModel)]="isAvailable" />
<label for="is-available">Is available</label>
`,
})
export class IsAvailableComponent {
isAvailable = signal(false);
}
Ember Polaris
import Component from "@glimmer/component";
import { tracked } from "@glimmer/tracking";
export default class InputHello extends Component {
@tracked isAvailable = false;
handleChange = (event) => (this.isAvailable = event.target.checked);
<template>
<input
id="is-available"
type="checkbox"
checked={{this.isAvailable}}
{{on "change" this.handleChange}}
/>
<label for="is-available">Is available</label>
</template>
}
Radio
Angular Renaissance
import { Component, signal } from "@angular/core";
import { FormsModule } from "@angular/forms";
@Component({
imports: [FormsModule],
selector: "app-pick-pill",
template: `
<div>Picked: {{ picked() }}</div>
<input id="blue-pill" type="radio" value="blue" [(ngModel)]="picked" />
<label for="blue-pill">Blue pill</label>
<input id="red-pill" type="radio" value="red" [(ngModel)]="picked" />
<label for="red-pill">Red pill</label>
`,
})
export class PickPillComponent {
picked = signal("red");
}
Ember Polaris
import Component from "@glimmer/component";
import { tracked } from "@glimmer/tracking";
export default class PickPill extends Component {
@tracked picked = "red";
handleChange = (event) => (this.picked = event.target.value);
<template>
<div>Picked: {{this.picked}}</div>
<input
id="blue-pill"
type="radio"
value="blue"
checked={{eq this.picked "blue"}}
{{on "change" this.handleChange}}
/>
<label htmlFor="blue-pill">Blue pill</label>
<input
id="red-pill"
type="radio"
value="red"
checked={{eq this.picked "red"}}
{{on "change" this.handleChange}}
/>
<label htmlFor="red-pill">Red pill</label>
</template>
}
Select
Angular Renaissance
import { Component, signal } from "@angular/core";
import { FormsModule } from "@angular/forms";
@Component({
imports: [FormsModule],
selector: "app-color-select",
template: `
<select [(ngModel)]="selectedColorId">
@for (let color of colors; track color) {
<option [value]="color.id" [disabled]="color.isDisabled">
{{ color.text }}
</option>
}
</select>
`,
})
export class ColorSelectComponent {
selectedColorId = signal(2);
colors = [
{ id: 1, text: "red" },
{ id: 2, text: "blue" },
{ id: 3, text: "green" },
{ id: 4, text: "gray", isDisabled: true },
];
}
Ember Polaris
import Component from "@glimmer/component";
import { tracked } from "@glimmer/tracking";
export default class ColorSelect extends Component {
@tracked selectedColorId = 2;
select = (event) => (this.selectedColorId = event.target.value);
isSelected = (colorId) => this.selectedColorId === colorId;
colors = [
{ id: 1, text: "red" },
{ id: 2, text: "blue" },
{ id: 3, text: "green" },
{ id: 4, text: "gray", isDisabled: true },
];
<template>
<select {{on "change" this.select}}>
{{#each this.colors as |color|}}
<option
value={{color.id}}
disabled={{color.isDisabled}}
selected={{this.isSelected color.id}}
>
{{color.text}}
</option>
{{/each}}
</select>
</template>
}
Webapp features
Render app
Angular Renaissance
<!doctype html>
<html>
<body>
<app-root></app-root>
</body>
</html>
Ember Polaris
<!doctype html>
<html>
<body>
<script type="module" src="./index.js"></script>
</body>
</html>
Fetch data
Angular Renaissance
import { Injectable } from "@angular/core";
import { httpResource } from "@angular/common/http";
@Injectable({ providedIn: "root" })
export class UserService {
readonly usersResource = httpResource<UserResponse>(
() => "https://randomuser.me/api/?results=3",
);
}
export interface UserResponse {
results: User[];
info: any;
}
export interface User {
name: {
title: string;
first: string;
last: string;
};
picture: {
large: string;
medium: string;
thumbnail: string;
};
}
Ember Polaris
import Component from "@glimmer/component";
import { tracked } from "@glimmer/tracking";
class State {
@tracked isLoading = false;
@tracked error = null;
@tracked data = null;
}
function fetchUsers() {
let state = new State();
async function fetchData() {
try {
let response = await fetch("https://randomuser.me/api/?results=3");
let { results: users } = await response.json();
state.data = users;
state.error = null;
} catch (err) {
state.data = null;
state.error = err;
}
state.isLoading = false;
}
fetchData();
return state;
}
export default class App extends Component {
<template>
{{#let (this.fetchUsers) as |request|}}
{{#if request.isLoading}}
<p>Fetching users...</p>
{{else if request.error}}
<p>An error occurred while fetching users</p>
{{else}}
<ul>
{{#each request.data as |user|}}
<li>
<img src={{user.picture.thumbnail}} alt="user" />
<p>{{user.name.first}} {{user.name.last}}</p>
</li>
{{/each}}
</ul>
{{/if}}
{{/let}}
</template>
}