Reactivity

Declare state

logo of Mithril Mithril

import m from "mithril";

export default function Name() {
  let name = "John";

  return {
    view: () => m("h1", `Hello ${name}`),
  };
}

logo of Ripple Ripple

import { track } from "ripple";

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

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

Update state

logo of Mithril Mithril

import m from "mithril";

export default function Name() {
  let name = "John";
  name = "Jane";
  return {
    view: () => m("h1", `Hello ${name}`),
  };
}

logo of Ripple Ripple

import { track } from "ripple";

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

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

Computed state

logo of Mithril Mithril

import m from "mithril";

export default function DoubleCount() {
  let count = 10;
  let doubleCount = count * 2;
  return {
    view: () => m("div", doubleCount),
  };
}

logo of Ripple Ripple

import { track } from "ripple";

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

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

Templating

Minimal template

logo of Mithril Mithril

import m from "mithril";

export default function HelloWorld() {
  return {
    view: () => m("h1", "Hello World"),
  };
}

logo of Ripple Ripple

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

Styling

logo of Mithril Mithril

import "./style.css";
import m from "mithril";

export default function CssStyle() {
  return {
    view: () =>
      m(
        "div",
        m("h1.title", "I am red"),
        m("button", { style: { fontSize: "10rem" } }, "I am a button"),
      ),
  };
}

logo of Ripple Ripple

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

logo of Mithril Mithril

import m from "mithril";

export default function Colors() {
  const colors = ["red", "green", "blue"];
  return {
    view: () =>
      m(
        "ul",
        colors.map((color, idx) => m("li", { key: idx }, color)),
      ),
  };
}

logo of Ripple Ripple

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

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

Event click

logo of Mithril Mithril

import m from "mithril";

export default function Counter() {
  let count = 0;
  const incrementCount = () => (count = count + 1);
  return {
    view: () =>
      m(
        "div",
        m("p", `Counter: ${count}`),
        m("button", { onclick: incrementCount }, "+1"),
      ),
  };
}

logo of Ripple Ripple

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

logo of Mithril Mithril

import m from "mithril";

export default function InputFocused() {
  let value = "";
  return {
    view: () =>
      m("input", {
        oncreate: ({ dom }) => dom.focus(),
        type: "text",
        value,
        oninput: (e) => (value = e.target.value),
      }),
  };
}

logo of Ripple Ripple

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

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

Conditional

logo of Mithril Mithril

import m from "mithril";
const TRAFFIC_LIGHTS = ["red", "orange", "green"];

export default function TrafficLight() {
  let lightIndex = 0;
  let currentLight = () => TRAFFIC_LIGHTS[lightIndex];

  const nextLight = () => (lightIndex + 1) % TRAFFIC_LIGHTS.length;

  const instructions = () => {
    switch (currentLight()) {
      case "red":
        return "STOP";
      case "orange":
        return "SLOW DOWN";
      case "green":
        return "GO";
    }
  };

  return {
    view: () =>
      m(
        "div",
        m("button", { onclick: nextLight }, "Next light"),
        m("p", `Light is: ${currentLight()}`),
        m("p", "You must ", m("span", instructions())),
      ),
  };
}

logo of Ripple Ripple

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

logo of Mithril Mithril

import m from "mithril";

export default function PageTitle() {
  return {
    view: () => m("p", `Page title: ${document.title}`),
  };
}

logo of Ripple Ripple

import { effect, track } from "ripple";

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

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

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

On unmount

logo of Mithril Mithril

import m from "mithril";

export default function Time() {
  let time = new Date().toLocaleTimeString();

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

  return {
    view: () => m("p", `Current time: ${time}`),
    onremove: () => clearInterval(timer),
  };
}

logo of Ripple Ripple

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

logo of Mithril Mithril

import m from "mithril";
import UserProfile from "./UserProfile.js";

export default function App() {
  return {
    view: () =>
      m(UserProfile, {
        name: "john",
        age: 20,
        favouriteColors: ["green", "blue", "red"],
        isAvailable: true,
      }),
  };
}

logo of Ripple Ripple

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

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

Emit to parent

logo of Mithril Mithril

import m from "mithril";
export const AnswerButton = ({ attrs: { onYes, onNo } }) => ({
  view: () =>
    m(
      "div",
      m("button", { onclick: onYes }, "YES"),
      m("button", { onclick: onNo }, "NO"),
    ),
});

logo of Ripple Ripple

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

logo of Mithril Mithril

import m from "mithril";
import { FunnyButton } from "./FunnyButton.jsx";

export default function App() {
  return {
    view: () => m(FunnyButton, "Click me!"),
  };
}

logo of Ripple Ripple

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

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

Slot fallback

logo of Mithril Mithril

import m from "mithril";
import FunnyButton from "./FunnyButton.jsx";

export default function App() {
  return {
    view: () => m("", m(FunnyButton), m(FunnyButton, "I got Content")),
  };
}

logo of Ripple Ripple

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

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

Context

logo of Mithril Mithril

import m from "mithril";
import UserProfile from "./UserProfile";

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

  const updateUsername = (username) => (user.username = username);

  return {
    view: () =>
      m(
        "",
        m("h1", `Welcome Back, ${user.username}`),
        m(UserProfile, { user, updateUsername }),
      ),
  };
}

logo of Ripple Ripple

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

logo of Mithril Mithril

import m from "mithril";

export default function InputHello() {
  let text = "Hello world";
  const handleChange = ({ target: { value } }) => (text = value);

  return {
    view: () =>
      m("", m("p", text), m("input", { value: text, onchange: handleChange })),
  };
}

logo of Ripple Ripple

import { bindValue, track } from "ripple";

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

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

Checkbox

logo of Mithril Mithril

import m from "mithril";

export default function IsAvailable() {
  let isAvailable = false;
  const onUpdate = () => (isAvailable = !isAvailable);

  return {
    view: () =>
      m(
        "",

        m("input", {
          id: "is-available",
          type: "checkbox",
          checked: isAvailable,
          onchange: onUpdate,
        }),
        m("label", { for: "is-available" }, "Is available"),
      ),
  };
}

logo of Ripple Ripple

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

logo of Mithril Mithril

import m from "mithril";

export default function PickPill() {
  let picked = "red";
  let pills = ["red", "green", "blue"];
  const handleChange = ({ target: { value } }) => (picked = value);

  return {
    view: () =>
      m(
        "",
        m("", `Picked: ${picked}`),
        pills.map((pill) =>
          m(
            ".",
            m("input", {
              id: pill,
              checked: picked == pill,
              type: "radio",
              value: pill,
              onchange: handleChange,
            }),
            m("label", { for: pill }, pill),
          ),
        ),
      ),
  };
}

logo of Ripple Ripple

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

logo of Mithril Mithril

import m from "mithril";
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 = 2;

  const handleSelect = ({ target: { value } }) => (selectedColorId = value);

  return {
    view: () =>
      m(
        "select",
        { value: selectedColorId, onchange: handleSelect },
        colors.map(({ id, text, isDisabled }) =>
          m("option", { key: id, id, disabled: isDisabled, value: id }, text),
        ),
      ),
  };
}

logo of Ripple Ripple

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

logo of Mithril Mithril

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

logo of Ripple Ripple

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

Fetch data

logo of Mithril Mithril

import m from "mithril";

export default function App() {
  let isLoading = false;
  let error = null;
  let users = [];

  async function fetchUsers() {
    isLoading = true;
    try {
      const { results } = await m.request(
        "https://randomuser.me/api/?results=3",
      );
      users = results;
    } catch (err) {
      error = err;
    }
    isLoading = false;
  }

  return {
    oninit: fetchUsers,
    view() {
      if (isLoading) return m("p", "Fetching users...");
      if (error) return m("p", "An error occurred while fetching users");
      return users.map((user) =>
        m(
          "li",
          { key: user.login.uuid },
          m("img", { src: user.picture.thumbnail, alt: "user" }),
          m("p", `${user.name.first} ${user.name.last}`),
        ),
      );
    },
  };
}

logo of Ripple Ripple

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>
    }
  </>;
}