Ember Octane vs Svelte 4 Comparison

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

<script>
  let name = "John";
</script>

<h1>Hello {name}</h1>

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

<script>
  let name = "John";
  name = "Jane";
</script>

<h1>Hello {name}</h1>

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

<script>
  let count = 10;
  $: doubleCount = count * 2;
</script>

<div>{doubleCount}</div>

<h1>Hello world</h1>

<h1>Hello world</h1>

/* using: https://github.com/salsify/ember-css-modules */
.title {
  color: red;
}

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

<style>
  .title {
    color: red;
  }
</style>

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

<script>
  const colors = ["red", "green", "blue"];
</script>

<ul>
  {#each colors as color (color)}
    <li>{color}</li>
  {/each}
</ul>

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

<script>
  let count = 0;

  function incrementCount() {
    count++;
  }
</script>

<p>Counter: {count}</p>
<button on:click={incrementCount}>+1</button>

<input {{this.autofocus}} />

<script>
  import { onMount } from "svelte";

  let inputElement;

  onMount(() => {
    inputElement.focus();
  });
</script>

<input bind:this={inputElement} />

<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>

<script>
  const TRAFFIC_LIGHTS = ["red", "orange", "green"];
  let lightIndex = 0;

  $: light = TRAFFIC_LIGHTS[lightIndex];

  function nextLight() {
    lightIndex = (lightIndex + 1) % TRAFFIC_LIGHTS.length;
  }
</script>

<button on:click={nextLight}>Next light</button>
<p>Light is: {light}</p>
<p>
  You must
  {#if light === "red"}
    <span>STOP</span>
  {:else if light === "orange"}
    <span>SLOW DOWN</span>
  {:else if light === "green"}
    <span>GO</span>
  {/if}
</p>

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

<script>
  import { onMount } from "svelte";
  let pageTitle = "";
  onMount(() => {
    pageTitle = document.title;
  });
</script>

<p>Page title: {pageTitle}</p>

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

<script>
  import { onDestroy } from "svelte";

  let time = new Date().toLocaleTimeString();

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

  onDestroy(() => clearInterval(timer));
</script>

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

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

<script>
  import UserProfile from "./UserProfile.svelte";
</script>

<UserProfile
  name="John"
  age={20}
  favouriteColors={["green", "blue", "red"]}
  isAvailable
/>

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

<script>
  import AnswerButton from "./AnswerButton.svelte";

  let isHappy = true;

  function onAnswerNo() {
    isHappy = false;
  }

  function onAnswerYes() {
    isHappy = true;
  }
</script>

<p>Are you happy?</p>
<AnswerButton on:yes={onAnswerYes} on:no={onAnswerNo} />
<p style="font-size: 50px;">{isHappy ? "😀" : "😥"}</p>

<FunnyButton> Click me! </FunnyButton>

<script>
  import FunnyButton from "./FunnyButton.svelte";
</script>

<FunnyButton>Click me!</FunnyButton>

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

<script>
  import FunnyButton from "./FunnyButton.svelte";
</script>

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

<UserProfile />

<script>
  import { setContext } from "svelte";
  import UserProfile from "./UserProfile.svelte";
  import createUserStore from "./createUserStore.js";

  const userStore = createUserStore({
    id: 1,
    username: "unicorn42",
    email: "unicorn42@example.com",
  });

  setContext("user", userStore);
</script>

<h1>Welcome back, {$userStore.username}</h1>
<UserProfile />

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

<script>
  let text = "Hello World";
</script>

<p>{text}</p>
<input bind:value={text} />

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

<script>
  let isAvailable = false;
</script>

<input id="is-available" type="checkbox" bind:checked={isAvailable} />
<label for="is-available">Is available</label>

<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>

<script>
  let picked = "red";
</script>

<div>Picked: {picked}</div>

<input id="blue-pill" bind:group={picked} type="radio" value="blue" />
<label for="blue-pill">Blue pill</label>

<input id="red-pill" bind:group={picked} type="radio" value="red" />
<label for="red-pill">Red pill</label>

<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>

<script>
  let selectedColorId = 2;

  const colors = [
    { id: 1, text: "red" },
    { id: 2, text: "blue" },
    { id: 3, text: "green" },
    { id: 4, text: "gray", isDisabled: true },
  ];
</script>

<select bind:value={selectedColorId}>
  {#each colors as color}
    <option value={color.id} disabled={color.isDisabled}>
      {color.text}
    </option>
  {/each}
</select>

<!DOCTYPE html>
<html>
  <body>
    <div id="app"></div>
    <script type="module" src="./app.js"></script>
  </body>
</html>

<!DOCTYPE html>
<html>
  <body>
    <div id="app"></div>
    <script type="module" src="./app.js"></script>
  </body>
</html>

{{#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}}

<script>
  import useFetchUsers from "./useFetchUsers";

  const { isLoading, error, data: users } = useFetchUsers();
</script>

{#if $isLoading}
  <p>Fetching users...</p>
{:else if $error}
  <p>An error occurred while fetching users</p>
{:else if $users}
  <ul>
    {#each $users as user}
      <li>
        <img src={user.picture.thumbnail} alt="user" />
        <p>
          {user.name.first}
          {user.name.last}
        </p>
      </li>
    {/each}
  </ul>
{/if}