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Component Party

Reactivity

Declare state

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<script>
  let name = $state("John");
</script>

<h1>Hello {name}</h1>

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import { track } from "ripple";

export default function Name() {
  let &[name] = track("John");

  return <h1>"Hello "{name}</h1>;
}

Update state

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<script>
  let name = $state("John");
  name = "Jane";
</script>

<h1>Hello {name}</h1>

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import { track } from "ripple";

export default function Name() {
  let &[name] = track("John");
  name = "Jane";

  return <h1>"Hello "{name}</h1>;
}

Computed state

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<script>
  let count = $state(10);
  const doubleCount = $derived(count * 2);
</script>

<div>{doubleCount}</div>

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import { track } from "ripple";

export default function DoubleCount() {
  let &[count] = track(10);
  let &[doubleCount] = track(() => count * 2);

  return <div>{doubleCount}</div>;
}

Templating

Minimal template

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<h1>Hello world</h1>

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export default function HelloWorld() {
  return <h1>"Hello world"</h1>;
}

Styling

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

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

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export default function CssStyle() {
  return <>
    <h1 class="title">"I am red"</h1>
    <button style={{ fontSize: "10rem" }}>"I am a button"</button>

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

Loop

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

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

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export default function Colors() {
  const colors = ["red", "green", "blue"];

  return <ul>
    for (const color of colors; key color) {
      <li>{color}</li>
    }
  </ul>;
}

Event click

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<script>
  let count = $state(0);

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

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

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import { track } from "ripple";

export default function Counter() {
  let &[count] = track(0);

  function incrementCount() {
    count++;
  }

  return <>
    <p>"Count: "{count}</p>
    <button onClick={incrementCount}>"+1"</button>
  </>;
}

Dom ref

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<script>
  let inputElement;

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

<input bind:this={inputElement} />

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export default function InputFocused() {
  function autofocus(element) {
    element.focus();
  }

  return <input ref={autofocus} />;
}

Conditional

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

  const light = $derived(TRAFFIC_LIGHTS[lightIndex]);

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

<button onclick={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>

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import { track } from "ripple";

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

export default function TrafficLight() {
  let &[lightIndex] = track(0);

  let &[light] = track(() => TRAFFIC_LIGHTS[lightIndex]);

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

  return <>
    <button onClick={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>
      }
    </p>
  </>;
}

Lifecycle

On mount

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<script>
  let pageTitle = $state("");
  $effect(() => {
    pageTitle = document.title;
  });
</script>

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

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import { effect, track } from "ripple";

export default function PageTitle() {
  let &[pageTitle] = track("");

  effect(() => {
    pageTitle = document.title;
  });

  return <h1>"Page title: "{pageTitle}</h1>;
}

On unmount

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<script>
  let time = $state(new Date().toLocaleTimeString());

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

    return () => clearInterval(timer);
  });
</script>

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

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import { effect, track } from "ripple";

export default function Time() {
  let &[time] = track(new Date().toLocaleTimeString());

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

    return () => clearInterval(timer);
  });

  return <h1>"Current time: "{time}</h1>;
}

Component composition

Props

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

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

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import { UserProfile } from "./UserProfile.tsrx";

export function App() {
  return <UserProfile
    name="John"
    age={20}
    favouriteColors={["green", "blue", "red"]}
    isAvailable
  />;
}

Emit to parent

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

  let isHappy = $state(true);

  function onAnswerNo() {
    isHappy = false;
  }

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

<p>Are you happy?</p>
<AnswerButton onYes={onAnswerYes} onNo={onAnswerNo} />
<p style="font-size: 50px;">{isHappy ? "😀" : "😥"}</p>

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import { track } from "ripple";

import { AnswerButton } from "./AnswerButton.tsrx";

export function App() {
  let &[isHappy] = track(true);

  function onAnswerNo() {
    isHappy = false;
  }

  function onAnswerYes() {
    isHappy = true;
  }

  return <>
    <p>"Are you happy?"</p>
    <AnswerButton onYes={onAnswerYes} onNo={onAnswerNo} />
    <p style={{ fontSize: "50px" }}>{isHappy ? "😀" : "😥"}</p>
  </>;
}

Slot

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

<FunnyButton>Click me!</FunnyButton>

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import { FunnyButton } from "./FunnyButton.tsrx";

export function App() {
  return <FunnyButton>"Click me!"</FunnyButton>;
}

Slot fallback

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

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

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import { FunnyButton } from "./FunnyButton.tsrx";

export function App() {
  return <>
    <FunnyButton />
    <FunnyButton>"I got content!"</FunnyButton>
  </>;
}

Context

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

  const user = createUserState({
    id: 1,
    username: "unicorn42",
    email: "[email protected]",
  });

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

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

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import { RippleObject } from "ripple";

import { UserContext } from "./UserContext.tsrx";
import { UserProfile } from "./UserProfile.tsrx";

export function App() {
  const user = new RippleObject({
    id: 1,
    username: "unicorn42",
    email: "[email protected]",
  });

  UserContext.set(user);

  return <>
    <h1>"Welcome back, "{user.username}</h1>
    <UserProfile />
  </>;
}

Form input

Input text

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<script>
  let text = $state("Hello World");
</script>

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

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import { bindValue, track } from "ripple";

export default function InputHello() {
  let &[text, textTracked] = track("Hello world");

  return <>
    <p>{text}</p>
    <input ref={bindValue(textTracked)} />
  </>;
}

Checkbox

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<script>
  let isAvailable = $state(false);
</script>

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

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import { bindChecked, track } from "ripple";

export default function IsAvailable() {
  let &[isAvailable, isAvailableTracked] = track(false);

  return <>
    <input
      id="is-available"
      type="checkbox"
      ref={bindChecked(isAvailableTracked)}
    />
    <label for="is-available">"Is available"</label>
  </>;
}

Radio

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<script>
  let picked = $state("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>

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import { bindGroup, track } from "ripple";

export default function PickPill() {
  let &[picked, pickedTracked] = track("red");

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

    <input
      id="blue-pill"
      type="radio"
      value="blue"
      ref={bindGroup(pickedTracked)}
    />
    <label for="blue-pill">"Blue pill"</label>

    <input
      id="red-pill"
      type="radio"
      value="red"
      ref={bindGroup(pickedTracked)}
    />
    <label for="red-pill">"Red pill"</label>
  </>;
}

Select

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<script>
  let selectedColorId = $state(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>

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import { bindValue, track } from "ripple";

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

export default function ColorSelect() {
  let &[selectedColorId, selectedColorIdTracked] = track(2);

  return <select ref={bindValue(selectedColorIdTracked)}>
    for (const color of colors; key color.id) {
      <option value={color.id} disabled={color.isDisabled}>
        {color.text}
      </option>
    }
  </select>;
}

Webapp features

Render app

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

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

Fetch data

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

  const response = useFetchUsers();
</script>

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

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import { useFetchUsers } from "./useFetchUsers.tsrx";

export function App() {
  const data = useFetchUsers();

  return <>
    if (data.isLoading) {
      <p>"Fetching users..."</p>
    } else if (data.error) {
      <p>"An error occurred while fetching users"</p>
    } else if (data.users) {
      <ul>
        for (const user of data.users; key user.login.uuid) {
          <li>
            <img src={user.picture.thumbnail} alt="user" />
            <p>{user.name.first}" "{user.name.last}</p>
          </li>
        }
      </ul>
    }
  </>;
}