响应式

声明状态

Svelte 5 标志 Svelte 5

<script>
  let name = $state("张三");
</script>

<h1>你好 {name}</h1>

Ripple 标志 Ripple

import { track } from "ripple";

export default function Name() {
  let &[name] = track("张三");

  return <h1>"你好 "{name}</h1>;
}

更新状态

Svelte 5 标志 Svelte 5

<script>
  let name = $state("张三");
  name = "李四";
</script>

<h1>你好 {name}</h1>

Ripple 标志 Ripple

import { track } from "ripple";

export default function Name() {
  let &[name] = track("张三");
  name = "李四";

  return <h1>"你好 "{name}</h1>;
}

计算属性

Svelte 5 标志 Svelte 5

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

<div>{doubleCount}</div>

Ripple 标志 Ripple

import { track } from "ripple";

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

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

模板语法

最简模板

Svelte 5 标志 Svelte 5

<h1>你好,世界</h1>

Ripple 标志 Ripple

export default function HelloWorld() {
  return <h1>"你好,世界"</h1>;
}

样式

Svelte 5 标志 Svelte 5

<h1 class="title">我是红色的</h1>
<button style="font-size: 10rem;">我是一个按钮</button>

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

Ripple 标志 Ripple

export default function CssStyle() {
  return <>
    <h1 class="title">"我是红色的"</h1>
    <button style={{ fontSize: "10rem" }}>"我是一个按钮"</button>

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

DOM循环

Svelte 5 标志 Svelte 5

<script>
  const colors = ["红", "绿", "蓝"];
</script>

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

Ripple 标志 Ripple

export default function Colors() {
  const colors = ["红", "绿", "蓝"];

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

点击事件

Svelte 5 标志 Svelte 5

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

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

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

Ripple 标志 Ripple

import { track } from "ripple";

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

  function incrementCount() {
    count++;
  }

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

DOM引用

Svelte 5 标志 Svelte 5

<script>
  let inputElement;

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

<input bind:this={inputElement} />

Ripple 标志 Ripple

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

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

条件渲染

Svelte 5 标志 Svelte 5

<script>
  const TRAFFIC_LIGHTS = ["红灯", "黄灯", "绿灯"];
  let lightIndex = $state(0);

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

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

<button onclick={nextLight}>下一个灯</button>
<p>现在亮着的是: {light}</p>
<p>
  你应该
  {#if light === "红灯"}
    <span>停下</span>
  {:else if light === "黄灯"}
    <span>慢行</span>
  {:else if light === "绿灯"}
    <span>赶紧走</span>
  {/if}
</p>

Ripple 标志 Ripple

import { track } from "ripple";

const TRAFFIC_LIGHTS = ["红灯", "黄灯", "绿灯"];

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}>"下一个灯"</button>
    <p>"现在亮着的是: "{light}</p>
    <p>
      "你应该 "
      if (light === "红灯") {
        <span>"停下"</span>
      } else if (light === "黄灯") {
        <span>"慢行"</span>
      } else if (light === "绿灯") {
        <span>"赶紧走"</span>
      }
    </p>
  </>;
}

生命周期

组件加载时

Svelte 5 标志 Svelte 5

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

<p>页面标题: {pageTitle}</p>

Ripple 标志 Ripple

import { effect, track } from "ripple";

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

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

  return <h1>"页面标题: "{pageTitle}</h1>;
}

组件卸载时

Svelte 5 标志 Svelte 5

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

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

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

<p>当前时间: {time}</p>

Ripple 标志 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>"当前时间: "{time}</h1>;
}

组件组合

组件Props传参

Svelte 5 标志 Svelte 5

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

<UserProfile
  name="张三"
  age={20}
  favouriteColors={["green", "blue", "red"]}
  isAvailable
/>

Ripple 标志 Ripple

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

export function App() {
  return <UserProfile
    name="张三"
    age={20}
    favouriteColors={["绿", "蓝", "红"]}
    isAvailable
  />;
}

向父组件emit事件

Svelte 5 标志 Svelte 5

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

  let isHappy = $state(true);

  function onAnswerNo() {
    isHappy = false;
  }

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

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

Ripple 标志 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>"你快乐吗?"</p>
    <AnswerButton onYes={onAnswerYes} onNo={onAnswerNo} />
    <p style={{ fontSize: "50px" }}>{isHappy ? "😀" : "😥"}</p>
  </>;
}

slot插槽

Svelte 5 标志 Svelte 5

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

<FunnyButton>点我!</FunnyButton>

Ripple 标志 Ripple

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

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

slot插槽内容

Svelte 5 标志 Svelte 5

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

<FunnyButton />
<FunnyButton>这是传到slot的内容!</FunnyButton>

Ripple 标志 Ripple

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

export function App() {
  return <>
    <FunnyButton />
    <FunnyButton>"这是传到slot的内容!"</FunnyButton>
  </>;
}

上下文

Svelte 5 标志 Svelte 5

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

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

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

<h1>欢迎回来, {user.username}</h1>
<UserProfile />

Ripple 标志 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: "abcdefg",
    email: "[email protected]",
  });

  UserContext.set(user);

  return <>
    <h1>"欢迎回来, "{user.username}</h1>
    <UserProfile />
  </>;
}

表单输入

输入框

Svelte 5 标志 Svelte 5

<script>
  let text = $state("你好世界");
</script>

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

Ripple 标志 Ripple

import { bindValue, track } from "ripple";

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

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

复选框

Svelte 5 标志 Svelte 5

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

<input id="is-available" type="checkbox" bind:checked={isAvailable} />
<label for="is-available">这是一个checkbox</label>

Ripple 标志 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">"这是一个checkbox"</label>
  </>;
}

单选框

Svelte 5 标志 Svelte 5

<script>
  let picked = $state("red");
</script>

<div>你选择了: {picked}</div>

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

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

Ripple 标志 Ripple

import { bindGroup, track } from "ripple";

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

  return <>
    <div>"你选择了: "{picked}</div>

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

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

选择器

Svelte 5 标志 Svelte 5

<script>
  let selectedColorId = $state(2);

  const colors = [
    { id: 1, text: "红" },
    { id: 2, text: "蓝" },
    { id: 3, text: "绿" },
    { id: 4, text: "灰", isDisabled: true },
  ];
</script>

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

Ripple 标志 Ripple

import { bindValue, track } from "ripple";

const colors = [
  { id: 1, text: "红" },
  { id: 2, text: "蓝" },
  { id: 3, text: "绿" },
  { id: 4, text: "灰", 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>;
}

Web应用特性

渲染应用

Svelte 5 标志 Svelte 5

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

Ripple 标志 Ripple

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

fetch获取数据

Svelte 5 标志 Svelte 5

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

  const response = useFetchUsers();
</script>

{#if response.isLoading}
  <p>正在获取用户信息……</p>
{:else if response.error}
  <p>获取用户信息出错</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}

Ripple 标志 Ripple

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

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

  return <>
    if (data.isLoading) {
      <p>"正在获取用户信息……"</p>
    } else if (data.error) {
      <p>"获取用户信息出错"</p>
    } else if (data.users) {
      <ul>
        for (const user of data.users; key user.login.uuid) {
          <li>
            <img src={user.picture.thumbnail} alt="用户" />
            <p>{user.name.first}" "{user.name.last}</p>
          </li>
        }
      </ul>
    }
  </>;
}