Component Party 标志

Component Party 中文版

响应式

声明状态

Lit 标志 Lit

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

@customElement("x-name")
export class XName extends LitElement {
  @state()
  name = "张三";

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

Aurelia 1 标志 Aurelia 1

<template>
  <h1>你好 ${name}</h1>
</template>

更新状态

Lit 标志 Lit

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

@customElement("x-name")
export class XName extends LitElement {
  @state()
  name = "张三";

  constructor() {
    super();
    this.name = "李四";
  }

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

Aurelia 1 标志 Aurelia 1

<template>
  <h1>你好 ${name}</h1>
</template>

计算属性

Lit 标志 Lit

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>`;
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <div>${doubleCount}</div>
</template>

模板语法

最简模板

Lit 标志 Lit

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

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

Aurelia 1 标志 Aurelia 1

<template>
  <h1>你好，世界</h1>
</template>

样式

Lit 标志 Lit

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">我是红色的</h1>
      <button style=${styleMap({ fontSize: "10rem" })}>我是一个按钮</button>
    `;
  }
}

Aurelia 1 标志 Aurelia 1

.title {
  color: red;
}

DOM循环

Lit 标志 Lit

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 = ["红", "绿", "蓝"];

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

Aurelia 1 标志 Aurelia 1

<template>
  <ul>
    <li repeat.for="color of colors">${color}</li>
  </ul>
</template>

点击事件

Lit 标志 Lit

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>计数器: ${this.count}</p>
      <button @click=${this.incrementCount}>+1</button>
    `;
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <p>计数器: ${count}</p>
  <button click.trigger="incrementCount()">+1</button>
</template>

DOM引用

Lit 标志 Lit

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" />`;
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <input ref="inputElement" />
</template>

条件渲染

Lit 标志 Lit

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

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

@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}>下一个灯</button>
      <p>现在亮着的是: ${this.light}</p>
      <p>
        你应该
        ${choose(this.light, [
          ["红灯", () => html`<span>停下</span>`],
          ["黄灯", () => html`<span>慢行</span>`],
          ["绿灯", () => html`<span>赶紧走</span>`],
        ])}
      </p>
    `;
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <button click.trigger="nextLight()">下一个灯</button>
  <p>现在亮着的是: ${light}</p>
  <p>
    你应该
    <span if.bind="light === '红灯'">停下</span>
    <span if.bind="light === '黄灯'">慢行</span>
    <span if.bind="light === '绿灯'">赶紧走</span>
  </p>
</template>

生命周期

组件加载时

Lit 标志 Lit

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>页面标题: ${this.pageTitle}</p>`;
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <p>页面标题: ${pageTitle}</p>
</template>

组件卸载时

Lit 标志 Lit

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>当前时间: ${this.time}</p>`;
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <p>当前时间: ${time}</p>
</template>

组件组合

组件Props传参

Lit 标志 Lit

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="张三"
      age="20"
      .favouriteColors=${["green", "blue", "red"]}
      isAvailable
    ></user-profile>`;
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <require from="./user-profile"></require>
  <user-profile
    name.bind="name"
    age.bind="age"
    favourite-colors.bind="colors"
    is-available.bind="available"
  ></user-profile>
</template>

向父组件emit事件

Lit 标志 Lit

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>你快乐吗?</p>
      <answer-button
        @yes=${this.onAnswerYes}
        @no=${this.onAnswerNo}
      ></answer-button>
      <p style="font-size: 50px;">${this.isHappy ? "😀" : "😥"}</p>
    `;
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <require from="./answer-button"></require>
  <p>你快乐吗?</p>
  <answer-button action-handler.call="handleAnswer(reply)"></answer-button>
  <p style="font-size: 50px">${isHappy ? "😀" : "😥"}</p>
</template>

slot插槽

Lit 标志 Lit

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>点我!</funny-button>`;
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <require from="./funny-button"></require>

  <funny-button>点我!</funny-button>
</template>

slot插槽内容

Lit 标志 Lit

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>这是传到slot的内容!</funny-button>
    `;
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <require from="./funny-button"></require>

  <funny-button></funny-button>
  <funny-button>这是传到slot的内容!</funny-button>
</template>

上下文

Lit 标志 Lit

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: "abcdefg",
    email: "[email protected]",
  };

  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>欢迎回来, ${this.user.username}</h1>
      <user-profile
        .user="${this.user}"
        .updateUsername=${this.updateUsername.bind(this)}
      ></user-profile>`;
  }
}

Aurelia 1 标志 Aurelia 1

缺少代码片段 帮助我们改进 Component Party Component Party 标志
在 Github 上贡献

表单输入

输入框

Lit 标志 Lit

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

@customElement("input-hello")
export class InputHello extends LitElement {
  @state()
  text = "你好世界";

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

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

Aurelia 1 标志 Aurelia 1

<template>
  <p>${text}</p>
  <input value.bind="text" />
</template>

复选框

Lit 标志 Lit

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">这是一个checkbox</label>
    `;
  }
}

Aurelia 1 标志 Aurelia 1

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

单选框

Lit 标志 Lit

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>你选择了: ${this.picked}</div>

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

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

Aurelia 1 标志 Aurelia 1

<template>
  <div>你选择了: ${picked}</div>

  <input id="blue-pill" checked.bind="picked" type="radio" value="blue" />
  <label for="blue-pill">蓝色</label>

  <input id="red-pill" checked.bind="picked" type="radio" value="red" />
  <label for="red-pill">红色</label>
</template>

选择器

Lit 标志 Lit

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: "红" },
    { id: 2, text: "蓝" },
    { id: 3, text: "绿" },
    { id: 4, text: "灰", 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>
    `;
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <select value.bind="selectedColorId">
    <option value="">选择一个颜色</option>
    <option
      repeat.for="color of colors"
      value.bind="color.id"
      disabled.bind="color.isDisabled"
    >
      ${color.text}
    </option>
  </select>
</template>

Web应用特性

渲染应用

Lit 标志 Lit

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

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

Aurelia 1 标志 Aurelia 1

缺少代码片段 帮助我们改进 Component Party Component Party 标志
在 Github 上贡献

fetch获取数据

Lit 标志 Lit

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>正在获取用户信息……</p>`,
      error: (e) => html`<p>获取用户信息出错</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>
      `,
    });
  }
}

Aurelia 1 标志 Aurelia 1

<template>
  <p if.bind="isLoading">正在获取用户信息……</p>
  <p if.bind="error">获取用户信息出错</p>
  <ul if.bind="users">
    <li repeat.for="user of users">
      <img src.bind="user.picture.thumbnail" alt="user" />
      <p>${ user.name.first } ${ user.name.last }</p>
    </li>
  </ul>
</template>