Lit vs Ember Octane comparison

Reactivity

Declare state

Lit

name.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";

@customElement("x-name")
export class XName extends LitElement {
  @state()
  name = "John";

  render() {
    return html`<h1>Hello ${this.name}!</h1>`;
  }
}

Ember Octane

name.hbs

<h1>Hello {{this.name}}</h1>

Update state

Lit

name.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";

@customElement("x-name")
export class XName extends LitElement {
  @state()
  name = "John";

  constructor() {
    super();
    this.name = "Jane";
  }

  render() {
    return html`<h1>Hello ${this.name}!</h1>`;
  }
}

Ember Octane

name.hbs

<h1>Hello {{this.name}}</h1>

Computed state

Lit

double-count.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";

@customElement("double-count")
export class DoubleCount extends LitElement {
  @state()
  count = 10;

  render() {
    const doubleCount = this.count * 2;
    return html`<div>${doubleCount}</div>`;
  }
}

Ember Octane

double-count.hbs

<div>{{this.doubleCount}}</div>

Templating

Minimal template

Lit

hello-world.js

import { LitElement, html } from "lit";
import { customElement } from "lit/decorators.js";

@customElement("hello-world")
export class HelloWorld extends LitElement {
  render() {
    return html`<h1>Hello world</h1>`;
  }
}

Ember Octane

hello-world.hbs

<h1>Hello world</h1>

Styling

Lit

css-style.js

import { LitElement, html, css } from "lit";
import { customElement } from "lit/decorators.js";
import { styleMap } from "lit/directives/style-map.js";

@customElement("css-style")
export class CssStyle extends LitElement {
  static styles = css`
    .title {
      color: red;
    }
  `;

  render() {
    return html`
      <h1 class="title">I am red</h1>
      <button style=${styleMap({ fontSize: "10rem" })}>I am a button</button>
    `;
  }
}

Ember Octane

css-style.hbs

<template>
  <h1 class="title">I am red</h1>
  <button style="font-size: 10rem">I am a button</button>
</template>

css-style.css

.title {
  color: red;
}

Loop

Lit

colors-list.js

import { LitElement, html } from "lit";
import { customElement } from "lit/decorators.js";
import { repeat } from "lit/directives/repeat.js";

@customElement("colors-list")
export class ColorsList extends LitElement {
  colors = ["red", "green", "blue"];

  render() {
    return html`
      <ul>
        ${repeat(
          this.colors,
          (color) => color,
          (color) => html`<li>${color}</li>`
        )}
      </ul>
    `;
  }
}

Ember Octane

colors.hbs

<ul>
  {{#each (array "red" "green" "blue") as |color|}}
    <li>{{color}}</li>
  {{/each}}
</ul>

Event click

Lit

x-counter.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";

@customElement("x-counter")
export class XCounter extends LitElement {
  @state()
  count = 0;

  incrementCount() {
    this.count = this.count + 1;
  }

  render() {
    return html`
      <p>Counter: ${this.count}</p>
      <button @click=${this.incrementCount}>+1</button>
    `;
  }
}

Ember Octane

counter.hbs

<p>Counter: {{this.count}}</p>
<button {{on "click" this.incrementCount}}>+1</button>

Dom ref

Lit

input-focused.js

import { LitElement, html } from "lit";
import { customElement, state, query } from "lit/decorators.js";

@customElement("input-focused")
export class InputFocused extends LitElement {
  @query("input") inputEl;

  firstUpdated() {
    this.inputEl.focus();
  }

  render() {
    return html`<input type="text" />`;
  }
}

Ember Octane

input-focused.hbs

<input {{this.autofocus}} />

Conditional

Lit

traffic-light.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";
import { choose } from "lit/directives/choose.js";

const TRAFFIC_LIGHTS = ["red", "orange", "green"];

@customElement("traffic-light")
export class TrafficLight extends LitElement {
  @state()
  lightIndex = 0;

  get light() {
    return TRAFFIC_LIGHTS[this.lightIndex];
  }

  nextLight() {
    this.lightIndex = (this.lightIndex + 1) % TRAFFIC_LIGHTS.length;
  }

  render() {
    return html`
      <button @click=${this.nextLight}>Next light</button>
      <p>Light is ${this.light}</p>
      <p>
        You must ${choose(this.light, [
          ["red", () => html`<span>STOP</span>`],
          ["orange", () => html`<span>SLOW DOWN</span>`],
          ["green", () => html`<span>GO</span>`],
        ])}
      </p>
    `;
  }
}

Ember Octane

traffic-light.hbs

<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>

Lifecycle

On mount

Lit

page-title.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";

@customElement("page-title")
export class PageTitle extends LitElement {
  @state()
  pageTitle = "";

  connectedCallback() {
    super.connectedCallback();
    this.pageTitle = document.title;
  }

  render() {
    return html`<p>Page title: ${this.pageTitle}</p>`;
  }
}

Ember Octane

page-title.hbs

<p>Page title is: {{(this.pageTitle)}}</p>

On unmount

Lit

x-time.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";

@customElement("x-time")
export class XTime extends LitElement {
  @state()
  time = "";

  timer;

  connectedCallback() {
    super.connectedCallback();
    this.timer = setInterval(() => {
      this.time = new Date().toLocaleTimeString();
    }, 1000);
  }

  disconnectedCallback() {
    super.disconnectedCallback();
    clearInterval(this.timer);
  }

  render() {
    return html`<p>Current time: ${this.time}</p>`;
  }
}

Ember Octane

time.hbs

<p>Current time: {{this.time}}</p>

Component composition

Props

Lit

x-app.js

import { LitElement, html } from "lit";
import { customElement } from "lit/decorators.js";

import "./user-profile";

@customElement("x-app")
export class XApp extends LitElement {
  render() {
    return html`<user-profile
      name="John"
      age="20"
      .favouriteColors=${["green", "blue", "red"]}
      isAvailable
    ></user-profile>`;
  }
}

Ember Octane

app.hbs

<UserProfile
  @name="John"
  @age={{20}}
  @favouriteColors={{array "green" "blue" "red"}}
  @isAvailable={{true}}
/>

Emit to parent

Lit

x-app.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";

import "./answer-button";

@customElement("x-app")
export class XApp extends LitElement {
  @state()
  isHappy = true;

  onAnswerNo() {
    this.isHappy = false;
  }

  onAnswerYes() {
    this.isHappy = true;
  }

  render() {
    return html`
      <p>Are you happy?</p>
      <answer-button
        @yes=${this.onAnswerYes}
        @no=${this.onAnswerNo}
      ></answer-button>
      <p style="font-size: 50px;">${this.isHappy ? "😀" : "😥"}</p>
    `;
  }
}

Ember Octane

app.hbs

<p>Are you happy?</p>
<AnswerButton @onYes={{this.handleYes}} @onNo={{this.handleNo}} />
<p style="font-size: 50px;">{{if this.isHappy "😀" "😥"}}</p>

Slot

Lit

x-app.js

import { LitElement, html } from "lit";
import { customElement } from "lit/decorators.js";

import "./funny-button";

@customElement("x-app")
export class XApp extends LitElement {
  render() {
    return html`<funny-button>Click me!</funny-button>`;
  }
}

Ember Octane

app.hbs

<FunnyButton> Click me! </FunnyButton>

Slot fallback

Lit

x-app.js

import { LitElement, html } from "lit";
import { customElement } from "lit/decorators.js";

import "./funny-button";

@customElement("x-app")
export class XApp extends LitElement {
  render() {
    return html`
      <funny-button></funny-button>
      <funny-button>Click me!</funny-button>
    `;
  }
}

Ember Octane

app.hbs

<FunnyButton />
<FunnyButton>I got content!</FunnyButton>

Context

Lit

app-x.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";
import { ContextProvider } from "@lit/context";

import { userContext } from "./user-context";

import "./user-profile";

@customElement("x-app")
export class XApp extends LitElement {
  @state()
  user = {
    id: 1,
    username: "unicorn42",
    email: "unicorn42@example.com",
  };

  provider = new ContextProvider(this, {
    context: userContext,
    initialValue: this.user,
  });

  updateUsername(newUsername) {
    this.user = { ...this.user, username: newUsername };
    this.provider.setValue(this.user);
  }

  render() {
    return html` <h1>Welcome back, ${this.user.username}</h1>
      <user-profile
        .user="${this.user}"
        .updateUsername=${this.updateUsername.bind(this)}
      ></user-profile>`;
  }
}

Ember Octane

app.hbs

<UserProfile />

Form input

Input text

Lit

input-hello.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";

@customElement("input-hello")
export class InputHello extends LitElement {
  @state()
  text = "Hello World";

  handleInput(event) {
    this.text = event.target.value;
  }

  render() {
    return html`
      <p>${this.text}</p>
      <input value=${this.text} @input=${this.handleInput} />
    `;
  }
}

Ember Octane

input-hello.hbs

<p>{{this.text}}</p>
<input value={{this.text}} {{on "input" this.handleInput}} />

Checkbox

Lit

is-available.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";

@customElement("is-available")
export class IsAvailable extends LitElement {
  @state()
  isAvailable = false;

  handleChange() {
    this.isAvailable = !this.isAvailable;
  }

  render() {
    return html`
      <input
        id="is-available"
        type="checkbox"
        ?checked=${this.isAvailable}
        @change=${this.handleChange}
      />
      <label for="is-available">Is available</label>
    `;
  }
}

Ember Octane

is-available.hbs

<input
  id="is-available"
  type="checkbox"
  checked={{this.isAvailable}}
  {{on "change" this.handleChange}}
/>
<label for="is-available">Is available</label>

Radio

Lit

pick-pill.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";

@customElement("pick-pill")
export class PickPill extends LitElement {
  @state()
  picked = "red";

  handleChange(event) {
    this.picked = event.target.value;
  }

  render() {
    return html`
      <div>Picked: ${this.picked}</div>

      <input
        id="blue-pill"
        name="pill"
        ?checked=${this.picked === "blue"}
        type="radio"
        value="blue"
        @change=${this.handleChange}
      />
      <label for="blue-pill">Blue pill</label>

      <input
        id="red-pill"
        name="pill"
        ?checked=${this.picked === "red"}
        type="radio"
        value="red"
        @change=${this.handleChange}
      />
      <label for="red-pill">Red pill</label>
    `;
  }
}

Ember Octane

pick-pill.hbs

<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>

Select

Lit

color-select.js

import { LitElement, html } from "lit";
import { customElement, state } from "lit/decorators.js";
import { repeat } from "lit/directives/repeat";

@customElement("color-select")
export class ColorSelect extends LitElement {
  colors = [
    { id: 1, text: "red" },
    { id: 2, text: "blue" },
    { id: 3, text: "green" },
    { id: 4, text: "gray", isDisabled: true },
  ];

  @state()
  selectedColorId = 2;

  handleChange(event) {
    this.selectedColorId = event.target.value;
  }

  render() {
    return html`
      <select @change=${this.handleChange}>
        ${repeat(
          this.colors,
          (color) => color.id,
          (color) =>
            html`<option
              value=${color.id}
              ?selected=${this.selectedColorId === color.id}
              ?disabled=${color.isDisabled}
            >
              ${color.text}
            </option>`
        )}
      </select>
    `;
  }
}

Ember Octane

color-select.hbs

<select {{on "change" this.select}}>
  {{#each this.colors as |color|}}
    <option
      value={{color.id}}
      disabled={{color.isDisabled}}
      selected={{eq color.id this.selectedColorId}}
    >
      {{color.text}}
    </option>
  {{/each}}
</select>

Webapp features

Render app

Lit

index.html

<!DOCTYPE html>
<html>
  <head>
    <script type="module" src="./app.js"></script>
  </head>

  <body>
    <x-app />
  </body>
</html>

Ember Octane

index.html

<template>
  <require from="./app"></require>
  <app></app>
</template>

Fetch data

Lit

x-app.js

import { LitElement, html } from "lit";
import { customElement } from "lit/decorators.js";
import { createFetchUsersTask } from "./fetch-users-task";

@customElement("x-app")
export class XApp extends LitElement {
  fetchUsers = createFetchUsersTask(this);

  render() {
    return this.fetchUsers.render({
      pending: () => html`<p>Fetching users...</p>`,
      error: (e) => html`<p>An error occurred while fetching users</p>`,
      complete: (data) => html`
        <ul>
          ${data.map(
            (user) => html`
              <li>
                <img src=${user.picture.thumbnail} alt="user" />
                <p>${user.name.first} ${user.name.last}</p>
              </li>
            `
          )}
        </ul>
      `,
    });
  }
}

Ember Octane

app.hbs

{{#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.users as |user|}}
        <li>
          <img src={{user.picture.thumbnail}} alt="user" />
          <p>{{user.name.first}} {{user.name.last}}</p>
        </li>
      {{/each}}
    </ul>

  {{/if}}
{{/let}}

Decouvrez plus d’Offres de la plateform ItGalaxy.io :

Découvrez notre gamme complète de services et formations pour accélérer votre carrière.

1. Nous contactez

Description: Besoin de Formation et des Solutions cloud complètes pour vos applications
Links:
- Nous contactez

2. Infra as a Service

Description: Infrastructure cloud évolutive et sécurisée
Links:
- Demandez un devis

3. Projets Développeurs

Description: Découvrez des opportunités passionnantes pour les développeurs
Links:

4. Développeurs

Description: Rejoignez notre communauté de développeurs
Links:
- DevOps
- Web
- Backend
- SEO
- Design
- Mobile
- Wordpress
- Shopify

5. Formations Complètes

Description: Accédez à des formations professionnelles de haute qualité
Links:

6. Marketplace

Description: Découvrez notre place de marché de services
Links:

7. Blogs

Description: Découvrez nos blogs
Links: