画皮卡丘、小黄人、哆啦A梦、瑞克和莫提、琦玉,任何CSS画出的非图片图形,Canvas SVG


目录 §


回顾技术栈

CSS3 + ES6综合应用

  • 必备知识:CSS3布局和定位、CSS3 transform、JS DOM操作

浏览器 JS 的能力

  • 操作DOM
  • 操作AJAX

目前的目标

  • 用jQuery操作DOM(之后改成Vue React)
  • 用axios操作AJAX

一个项目

  • 60%的时间在写CSS 布局
  • 20%的时间在写JS
  • 20%的时间在想错在哪

选择模仿目标

勿原创,不是设计师

  • 模仿别人的界面,代码自己写
  • codepen.io

项目介绍

特点

  • 移动端支持
  • CSS绘制任意图形,并同步显示代码
  • 界面简洁友好
  • 使用指南

技术栈

  • SCSS
  • parcel实时预览
  • @media媒体查询
  • 表驱动编程-自动绑定事件
  • Git & GitHub
  • 短链处理
  • 二维码链接

后续更新

  • vue版本
  • react版本

思路

  • 实现手机端
    • 写 HTML
    • 写 SCSS
    • 写 JS(事件监听、DOM 操作)
  • 实现PC端
    • 加 媒体查询 CSS
    • 写 JS(单独处理PC端逻辑)
  • 发布到 GitHub Gitee

创建和使用

开发

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yarn global add parcel-bundler
parcel src/index.html

build 命令

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yarn build

修改 package.json

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{
  "devDependencies": {
    "sass": "^1.26.9"
  },
  "scripts": {
    "build": "rm -rf dist && parcel build src/index.html --no-minify --public-url ./"
  }
}

取色工具 Snipaste


制作过程

index.html

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<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
  <meta name="viewport"
    content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no,viewport-fit=cover">
  <title>PiKaChu</title>
  <link rel="stylesheet" href="https://cdn.bootcdn.net/ajax/libs/modern-normalize/0.6.0/modern-normalize.min.css">
  <link rel="stylesheet" href="style.scss">
</head>
<body>
  <div class="face">
    <div class="eye"></div>
    <div class="eye eye-right"></div>
    <div class="noseTip"></div>
    <div class="cheek">
      <div class="cheek-left"></div>
      <div class="cheek-right"></div>
    </div>
    <div class="mouth">
      <div class="lip">
        <div class="lip-left"></div>
        <div class="lip-right"></div>
      </div>
      <div class="jaw">
        <div class="lowerJaw"></div>
      </div>
    </div>
  </div>
  <script src="main.js"></script>
</body>

基础SCSS样式

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*,
*::before,
*::after {
  box-sizing: border-box;
}
body {
  width: 100vw;
  min-height: 100vh;
  background-color: #ffe035;
}

@mixin widthHeight($width: 0px, $height: 0px) {
  width: $width;
  height: $height;
}

@function boxSize($width: 0px, $height: false) {
  @if $height==false {
    $height: $width;
  }

  // @warn $width;
  // @warn $height;
  // while invoke need `...`
  @return ($width, $height);
}

%pseudo {
  content: '';
  display: block;
}

制作鼻子和眼睛样式

以页面宽度中线为基准,画鼻子

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/* ... */
@mixin widthHeight($width: 0px, $height: 0px) {
  width: $width;
  height: $height;
}
%pseudo {
  content: '';
  display: block;
}
/* ... */
.face {
  position: relative;

  .noseTip {
    z-index: 2;
    position: absolute;
    left: 50%;
    top: 310px;
    margin-left: -10px;

    border: 10px solid #ffe035;
    border-top-color: black;
    border-bottom-width: 0px; // border-bottom: none;

    // Nasal bridge
    &::before {
      @extend %pseudo;
      @include widthHeight(20px, 10px);

      position: absolute;
      top: -16px;
      left: -10px;

      background-color: black;
      border-radius: 10px / 5px;
      box-shadow: 0px 0px 1px 0px black;
    }
  }
  .eye{
  //...
  }
  .cheek{
  //...
  }
  .mouth{
  //...
  }
}
  • 注意当写border 不同方向上数值的时候, 指的是那个方向上的厚度
  • CSS用border模拟图形(三角 + 圆/椭圆)
  • tips提示条
  • 各同级元素的单位保持一致(px / em ),和百分比 / vh vm 混用注意
  • 使用绝对定位时,没有普通文档流元素,body 元素高度设为{min-height: 100vh;}
  • 对具体某个元素使用绝对定位时,父元素设为相对定位
  • 平滑椭圆边线圆弧 border-bottom-left-radius: 60px 30px;
  • transform属性会相互覆盖,必须一次性写出transform: translate(110px, -30px) scaleX(-1) rotate(-20deg);

制作眼睛

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  .eye {
    border: 2px solid #000;
    @include widthHeight(boxSize(64px)...);
    background: #2e2e2e;
    border-radius: 100%;

    position: absolute;
    top: 270px;
    left: 50%;
    margin-left: -32px;
    transform: translateX(-150px);

    &-right {
      transform: translateX(150px);
      ;
    }

    // pupil
    &::before {
      @extend %pseudo;
      @include widthHeight(boxSize(30px)...);
      border-radius: 100%;
      background-color: whitesmoke;
      position: relative;
      left: 5px;
      top: 5px;
    }
  }

制作上嘴唇

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  .mouth {
    @include widthHeight(220px, 200px);
    position: absolute;
    left: 50%;
    top: 350px;
    margin-left: -110px;

    .lip {
      z-index: 1;
      position: relative;

      %lips {
        background-color: #ffe035;
        @include widthHeight(110px, 30px);

        border: 4px solid black;
        border-top-width: 0px;
        border-right-width: 0px;
        border-top-color: #ffe035;
        border-top-right-radius: 60px 30px;

        // mustache hide lip
        &::after {
          @extend %pseudo;

          @include widthHeight(100%, 0.01px);
          border: 2px solid #ffe035;
          outline: 1px solid #ffe035;
          position: absolute;
          top: -3px;
          left: 1px;
        }
      }

      @mixin border($bd-b-l-rad: 60px 30px, $rotate:rotate(-20deg)) {
        border-bottom-left-radius: $bd-b-l-rad;
        transform: $rotate;
      }

      &>.lip-left {
        @extend %lips;
        @include border;
      }

      &>.lip-right {
        @extend %lips;
        @include border(60px 30px, translate(110px, -30px) scaleX(-1) rotate(-20deg));
      }
    }
    .jaw{
        //...
    }
  }

制作下嘴唇

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    .jaw {
      @include widthHeight(100%, 220px);

      position: absolute;
      top: 8px;

      // hide lower jaw
      overflow: hidden;
      border-radius: 50% 50% 00/ 25% 25% 0 0;

      .lowerJaw {
        $jaw-width: 180px;
        @include widthHeight($jaw-width, 580px);

        position: absolute;
        bottom: 0;
        left: 50%;
        margin-left: -($jaw-width)/2;

        border: 3px solid #000;
        border-radius: 50% / 50%;
        background-color: #9b000a;

        // hide tongue
        overflow: hidden;

        // tongue
        &::after {
          @extend %pseudo;
          $tongue-width: 200px;
          $tongue-height: 380px;
          @include widthHeight($tongue-width, $tongue-height);
          background-color: #ff485f;

          position: absolute;
          bottom: -$tongue-height/2;
          left: 50%;
          margin-left: -$tongue-width/2;
          border-radius: 100px;
        }
      }
    }

添加动态效果

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.noseTip{
    /* ... */
    $n: 5deg;
    $step: 33%;

    @keyframes shakeNose {
      0% {
        transform: rotate(0deg);
      }

      @for $i from 1 to 3 {
        #{$i * $step} {
          @if $i % 2==0 {
            transform: rotate(-$n);
          }

          @else {
            transform: rotate($n);
          }
        }
      }

      100% {
        transform: rotate(0);
      }
    }

    &:hover {
      transform-origin: center bottom;
      animation: shakeNose infinite 300ms linear;
    }
}

移动端适配

px -> rem


动态显示代码

简单的测试

蹦字

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// <div id="demo"></div>
let n = 1;
const string = `大家好,我是这里是`;
demo.innerHTML = string.substr(0, n);
// console.log(n);
let id = setInterval(() => {
    n += 1;
    // console.log(n + ':' + string.substr(0, n) + '/' + string.length);
    if(n > string.length){
        window.clearInterval(id);
        return
    }
    demo.innerHTML = string.substr(0, n);
    console.log(n);
}, 300);

动态样式

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let n = 1;
// const string = `大家好,我是这里是`;
const string = `
<style>
    body {
    background-color: red;
    }
</style>
`;
demo.innerHTML = string.substr(0, n);
// console.log(n);
let id = setInterval(() => {
    n += 1;
    // console.log(n + ':' + string.substr(0, n) + '/' + string.length);
    if(n > string.length){
        window.clearInterval(id);
        return
    }
    demo.innerHTML = string.substr(0, n);
    console.log(n);
}, 300);

同时以文本和HTML的形式展示style标签

同时输出两种形式,一个用 innerHTML,另一个用innerText

  • innerText,以文本形式展示,但标签不会生效
  • 同时用innerHTML写入标签

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    // <div id="demo"></div>
    // <div id="demo2"></div>
    const string = `
    <style>
    body {
    background-color: red;
    }
    </style>
    `;
    let n = 1;
    demo.innerText = string.substr(0, n);
    demo2.innerHTML = string.substr(0, n);
    // console.log(n);
    let id = setInterval(() => {
    n += 1;
    // console.log(n + ':' + string.substr(0, n) + '/' + string.length);
    if(n > string.length){
        window.clearInterval(id);
        return
    }
    demo.innerText = string.substr(0, n);
    demo2.innerHTML = string.substr(0, n);
    console.log(n);
    }, 100);
    

先写好HTML到 <div id="html"></div>

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<div id="html">
    <div class="face">
        <div class="eye"></div>
        <div class="eye eye-right"></div>
        <div class="nose-tip "></div>
        <div class="cheek">
            <div class="cheek-left"></div>
            <div class="cheek-right"></div>
        </div>
        <div class="mouth">
            <div class="lip">
                <div class="lip-left"></div>
                <div class="lip-right"></div>
            </div>
            <div class="jaw">
                <div class="lower-jaw"></div>
            </div>
        </div>
    </div>
</div>

再动态显示 CSS 代码 动态加载CSS

  • 分屏固定显示代码文本和效果
  • 隐藏展示样式#demo2的代码,不影响效果
  • 写自动滚动到底部的代码,每写一句,就往下拉滚动条
  • 滚动距离为 可滚动高度 demo.scrollHeight,再减去滚动条本身的高度
  • 下拉的距离等于滚动的高度demo.scrollTop = demo.scrollHeight
  • 对JS来说,有没有滚动条,都可以滚动页面,只是用户不能操作滚动,设置overflow-y: auto
  • 或者用另一种隐藏滚动条的方法(搜CSS 隐藏滚动条) #demo::-webkit-scrollbar{display: none;}只是只能效果上看不见,仍可以用滚轮滚动页面

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    <style>
    #demo2{
        display: none;
    }
    #demo {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 30vh;
        border: 1px solid red;
        overflow: scroll;
    }
    #html {
        position: fixed;
        bottom: 0;
        left: 0;
        width: 100%;
        height: 80vh;
    }
    </style>

优化

  • 先写好style标签,将#demo2的div标签改为style标签
  • 去除会影响页面整体样式的代码,写到别处,或者用BootCDN 的normalize.css
  • 只显示对页面有直观效果的CSS代码

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    <body>
    <style id="demo2"></style>
    <div id="demo"></div>
    <style>
    #demo2{
        display: none;
    }
    #demo {
        background-color: whitesmoke;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 30vh;
        border: 1px solid red;
        overflow-y: auto;
    }
    #demo::-webkit-scrollbar{
        display: none;
    }
    #html {
        position: fixed;
        bottom: 0;
        left: 0;
        width: 100%;
        height: 80vh;
    }
    </style>
    <div id="html">
    <div class="face">
        <div class="eye"></div>
        <div class="eye eye-right"></div>
        <div class="nose-tip "></div>
        <div class="cheek">
            <div class="cheek-left"></div>
            <div class="cheek-right"></div>
        </div>
        <div class="mouth">
            <div class="lip">
                <div class="lip-left"></div>
                <div class="lip-right"></div>
            </div>
            <div class="jaw">
                <div class="lower-jaw"></div>
            </div>
        </div>
    </div>
    </div>
    <script src="test.js"></script>
    </body>

抽出默认样式代码

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const stringDefault = `
.face .nose-tip::after, .face .nose-tip::before, .face .eye::before, .face .mouth .lip > .lip-left::after, .face .mouth .lip > .lip-right::after, .face .mouth .jaw .lower-jaw::after {
  content: '';
  display: block;
}

.face .cheek {
  z-index: 2;
}
`;

抽出动画代码

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const stringAnimation = `
@keyframes shakeNose {
  0% {
    transform: rotate(0deg);
  }
  33% {
    transform: rotate(5deg);
  }
  66% {
    transform: rotate(-5deg);
  }
  100% {
    transform: rotate(0);
  }
}

.face .nose-tip:hover {
  animation: shakeNose infinite 300ms linear;
  transform-origin: center bottom;
}
`;

抽出string样式代码

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const string = `
body {
  background-color: #ffe035;
  min-height: 100vh;
  width: 100vw;
}

.face {
  min-height: 35vh;
  height: 300px;
  left: 50%;
  position: absolute;
  top: 50%;
  transform: translateY(-50%) translateX(-50%);
  width: 500px;
}

.face .nose-tip {
  border: 10px solid #ffe035;
  border-bottom-width: 1px;
  border-left-color: #ffe035;
  border-right-color: #ffe035;
  border-top-color: #000;
  left: 50%;
  margin-left: -10px;
  position: absolute;
  top: 100px;
  z-index: 2;
}

.face .nose-tip::after {
  height: 22px;
  width: 22px;
  border: 3px solid #ffe035;
  border-radius: 0 0 12px 12px / 0 0 20px 20px;
  border-top-color: transparent;
  left: -11px;
  overflow: hidden;
  position: absolute;
  top: -11px;
  z-index: 1;
}

.face .nose-tip::before {
  height: 10px;
  width: 20px;
  background-color: #000;
  border-radius: 10px / 5px;
  left: -10px;
  position: absolute;
  top: -16px;
}

.face .eye {
  height: 64px;
  width: 64px;
  background: #2e2e2e;
  border: 2px solid #000;
  border-radius: 100%;
  left: 50%;
  margin-left: -32px;
  position: absolute;
  top: 70px;
  transform: translateX(-150px);
}

.face .eye-right {
  transform: translateX(150px);
}

.face .eye::before {
  height: 30px;
  width: 30px;
  background-color: #f5f5f5;
  border-radius: 50%;
  left: 5px;
  position: relative;
  top: 5px;
}

.face .cheek .cheek-left, .face .cheek .cheek-right {
  height: 86px;
  width: 86px;
  background-color: #f00;
  border: 2px solid #000;
  border-radius: 50%;
  left: 50%;
  margin-left: -43px;
  position: absolute;
  top: 180px;
}

.face .cheek-left {
  transform: translateX(-180px);
}

.face .cheek-right {
  transform: translateX(180px);
}

.face .mouth {
  height: 200px;
  width: 220px;
  left: 50%;
  margin-left: -110px;
  position: absolute;
  top: 135px;
}

.face .mouth .lip > .lip-left, .face .mouth .lip > .lip-right {
  height: 30px;
  width: 110px;
  background-color: #ffe035;
  border: 4px solid #000;
  border-top-color: #ffe035;
  border-top-right-radius: 60px 30px;
  border-top-width: 0;
  border-right-width: 0;
}

.face .mouth .lip > .lip-left::after, .face .mouth .lip > .lip-right::after {
  height: 0.01px;
  width: 100%;
  border: 2px solid #ffe035;
  left: 1px;
  outline: 1px solid #ffe035;
  position: absolute;
  top: -3px;
}

.face .mouth .lip {
  position: relative;
  z-index: 1;
}

.face .mouth .lip > .lip-left {
  border-bottom-left-radius: 60px 30px;
  transform: rotate(-20deg);
}

.face .mouth .lip > .lip-right {
  border-bottom-left-radius: 60px 30px;
  transform: translate(110px, -30px) scaleX(-1) rotate(-20deg);
}

.face .mouth .jaw {
  height: 220px;
  width: 100%;
  border-radius: 50% 50% 0 0 / 25% 25% 0 0;
  overflow: hidden;
  position: absolute;
  top: 8px;
}

.face .mouth .jaw .lower-jaw {
  height: 580px;
  width: 180px;
  background-color: #9b000a;
  border: 3px solid #000;
  border-radius: 50% / 50%;
  bottom: 0;
  left: 50%;
  margin-left: -90px;
  overflow: hidden;
  position: absolute;
}

.face .mouth .jaw .lower-jaw::after {
  height: 380px;
  width: 200px;
  background-color: #ff485f;
  border-radius: 100px;
  bottom: -190px;
  left: 50%;
  margin-left: -100px;
  position: absolute;
}
`;

模块化导出JS独立代码

将不相关的独立代码写到单独的文件中,导出,在需要的时候导入

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// 模块化
import stringDefault from './stringDefault.js';
import string from './string.js';
import stringAnimation from './stringAnimation.js';

stringDefault.js

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const stringDefault = `
`
export default stringDefault;

string.js

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const string = `
`
export default string;

stringAnimation.js

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const stringAnimation = `
`
export default stringAnimation;

集中导入

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// 模块化
import stringDefault from './stringDefault.js';
import string from './string.js';
import stringAnimation from './stringAnimation.js';

let n = 1;
demo.innerText = string.substr(0, n);
demo2.innerHTML = stringDefault + string.substr(0, n);
// console.log(n);
let id = setInterval(() => {
    n += 1;
    // console.log(n + ':' + string.substr(0, n) + '/' + string.length);
    if(n > string.length){
        window.clearInterval(id);
        demo2.innerHTML += stringAnimation;
        return
    }
    demo.innerText = string.substr(0, n);
    demo2.innerHTML = stringDefault + string.substr(0, n);
    // console.log(n);
    demo.scrollTop = demo.scrollHeight;
}, 0);
  • 导出的可以使变量、函数等
  • 重构代码

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    const run = () => {
    n += 1;
    if(n > string.length){
        window.clearInterval(id);
        demo2.innerHTML += stringAnimation;
        return
    }
    demo.innerText = string.substr(0, n);
    demo2.innerHTML = stringDefault + string.substr(0, n);
    demo.scrollTop = demo.scrollHeight;
    }
    

添加暂停、变速按钮

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<div id="demo"></div>
<div id="buttons">
    <button id="btnPause">暂停</button>
    <button id="btnPlay">播放</button>
    <button id="btnSlow">快速</button>
    <button id="btnNormal">超快速</button>
    <button id="btnFast">最快速</button>
</div>
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#buttons {
    position: fixed;
    top: 0;
    right: 0;
    z-index: 10;
    display: flex;
    flex-direction: column;
    margin-top: 20px;
    margin-right: 20px;
}

#buttons>button {
    margin-bottom: 10px;
}

@media ( min-width: 320px) and (max-width: 720px) {
    #buttons>button {
        padding: 4px 8px;
        font-size: 20px;
    }
}

暂停就是取消计时器,播放就是再设置一个计时器,变速就是更改间隔秒数

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// 暂停:取消计时器
btnPause.onclick = () => {
    window.clearInterval(id);
}
// 播放:再设置一个计时器
btnPlay.onclick = () => {
    id = setInterval( ()=>{
        run();
    }, intervalTime);
}
// 变速:更改间隔秒数
let intervalTime = 80;
btnSlow.onclick = () =>{
    window.clearInterval(id);
    let intervalTime = 80;
    id = setInterval(run, intervalTime);
};

重复即丑,重构JS代码

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btnSlow.onclick = () =>{
    window.clearInterval(id);
    let intervalTime = 80;
    id = setInterval(run, intervalTime);
};
btnNormal.onclick = () => {
    window.clearInterval(id);
    let intervalTime = 16;
    id = setInterval(run, intervalTime);
};
btnFast.onclick = () => {
    window.clearInterval(id);
    let intervalTime = 0;
    id = setInterval(run, intervalTime);
};

按作用抽象成函数,重构后的代码,主逻辑清晰

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// const run = () => {...}
// const play = () => {...}
// const pause = () => {...}

const run = () => {
    n += 1;
    if(n > string.length){
        window.clearInterval(id);
        demo2.innerHTML += stringAnimation;
        return
    }
    demo.innerText = string.substr(0, n);
    demo2.innerHTML = stringDefault + string.substr(0, n);
    demo.scrollTop = demo.scrollHeight;
}
const play = () => {
    setInterval(run, intervalTime);
}
const pause = () => {
    window.clearInterval(id);
}
let id = play();

把相似的代码封装成一个函数,取个名字,调用它

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btnPause.onclick = () => {
    pause();
}
btnPlay.onclick = () => {
    id = play();
}
btnSlow.onclick = () =>{
    pause();
    let intervalTime = 80;
    id = play();
};
btnNormal.onclick = () => {
    pause();
    let intervalTime = 16;
    id = play();
};
btnFast.onclick = () => {
    pause();
    let intervalTime = 0;
    id = play();
};

抽象事件函数,再重构

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// let intervalTime = 80;
// const run = () => {...}
// const play = () => {...}
// const pause = () => {...}
// const slow = () => {...}
// const normal = () => {...}
// const fast = () => {...}
const slow = () => {
    pause();
    intervalTime = 80;
    id = play();
}
const normal = () => {
    pause();
    intervalTime = 16;
    id = play();
}
const fast = () => {
    pause();
    intervalTime = 0;
    id = play();
}
// ...

btnSlow.onclick = slow;
btnNormal.onclick = normal;
btnFast.onclick = fast;

使用正规的语法,获取元素

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const demo = document.querySelector('#demo');
const demo2 = document.querySelector('#demo2');
/* 以下之后可以省略到属性 eventBind 里 document.querySelector(key).onclick = player[value]; */
const btnPause = document.querySelector('#btnPause');
const btnPlay = document.querySelector('#btnPlay');
const btnSlow = document.querySelector('#btnSlow');
const btnNormal = document.querySelector('#btnNormal');
const btnFast = document.querySelector('#btnFast');

用面向对象,再重构

  • 先声明const player = {...},后使用let id = player.play();
  • player.run
  • player.pause

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    //init
    // 先声明 n, 再使用 n
    let n = 1;
    demo.innerText = string.substr(0, n);
    demo2.innerHTML = stringDefault + string.substr(0, n);
    
    // let intervalTime = 80;
    // const run = () => {...}
    // const play = () => {...}
    // const pause = () => {...}
    // let id = play();
    // const slow = () => {...}
    // const normal = () => {...}
    // const fast = () => {...}
    // btnPause.onclick = pause;
    // btnPlay.onclick = () => {...}
    // btnSlow.onclick = slow;
    // btnNormal.onclick = normal;
    // btnFast.onclick = fast;
    
    // init
    let intervalTime = 80;
    let n = 1;
    
    const player = {
    run:() => {
        n += 1;
        if(n > string.length){
            window.clearInterval(id);
            demo2.innerHTML += stringAnimation;
            return
        }
        demo.innerText = string.substr(0, n);
        demo2.innerHTML = stringDefault + string.substr(0, n);
        demo.scrollTop = demo.scrollHeight;
    },
    play:() => {
        return setInterval(player.run, intervalTime);
    },
    pause: () => {
        window.clearInterval(id);
    },
    slow: () => {
        player.pause();
        intervalTime = 80;
        id = player.play();
    },
    normal: () => {
        player.pause();
        intervalTime = 16;
        id = player.play();
    },
    fast: () => {
        player.pause();
        intervalTime = 0;
        id = player.play();
    }
    };
    
    let id = player.play();
    
    btnPause.onclick = player.pause;
    btnPlay.onclick = () => {
    id = player.play();
    }
    btnSlow.onclick = player.slow;
    btnNormal.onclick = player.normal;
    btnFast.onclick = player.fast;
    

初始化方法

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// ...
let n = 1;
let intervalTime = 80;
let id; // id初始化放外面
const player = {
    init: () => {
        demo.innerText = string.substr(0, n);
        demo2.innerHTML = stringDefault + string.substr(0, n);
        id = player.play();
    },
    // ...
}
player.init();

内置功能 id = player.play();player.play

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const player = {    
    //...
    play:() => {
            player.pause();
            //return setInterval(player.run, intervalTime);
            id = setInterval(player.run, intervalTime);
        },
    slow: () => {
        player.pause();
        intervalTime = 80;
        // id = player.play();
        player.play();
    },
    normal: () => {
        player.pause();
        intervalTime = 16;
        // id = player.play();
        player.play();
    },
    fast: () => {
        player.pause();
        intervalTime = 0;
        // id = player.play();
        player.play();
    },
    //...
}
    //...
    btnPlay.onclick = player.play();

将绑定事件放入初始化函数

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const player = {
    init: () => {
        demo.innerText = string.substr(0, n);
        demo2.innerHTML = stringDefault + string.substr(0, n);
        player.play();
        player.eventBind();
    },
    eventBind: () => {
        console.log("绑定了事件");
        btnPause.onclick = player.pause;
        btnPlay.onclick = player.play;
        btnSlow.onclick = player.slow;
        btnNormal.onclick = player.normal;
        btnFast.onclick = player.fast;
    },
    // ...
}

表驱动编程:哈希Map 避免重复代码声明事件

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const player = {
    init: () => {
    demo.innerText = string.substr(0, n);
    demo2.innerHTML = stringDefault + string.substr(0, n);
    player.play();
    player.eventBind(); // `player.eventBind()`是`player.init()`执行后才执行的;再去绑定事件是可以的
    },
    eventBind: () => {
     // `player.eventBind()`是`player.init()`执行后才执行的;再去绑定事件是可以的
        const events = {
            '#btnPause': player.pause,
            '#btnPlay': player.play,
            '#btnSlow': player.slow,
            '#btnNormal': player.normal,
            '#btnFast': player.fast
        };
        for(let key in events) {
            document.querySelector(key).onclick = events[key];
        }
    },
    //...
}

将hashTable放到声明中去

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const player = {
    init: () => {
    demo.innerText = string.substr(0, n);
    demo2.innerHTML = stringDefault + string.substr(0, n);
    player.play();
    player.eventBind();
    },
    // 在声明player时用使用player,报错 player 是 undefined
    events : {
        '#btnPause': player.pause, // 报错 在定义对象时调用此对象
        '#btnPlay': player.play, // 报错 在定义对象时调用此对象
        '#btnSlow': player.slow, // 报错 在定义对象时调用此对象
        '#btnNormal': player.normal, // 报错 在定义对象时调用此对象
        '#btnFast': player.fast // 报错 在定义对象时调用此对象
    },
    eventBind: () => {
        for(let key in events) {
            document.querySelector(key).onclick = events[key];
        }
    },
    //...
}
  • 哈希Map,读取字符串
  • 不能在定义对象时调用此对象
  • 区别于函数,函数可以延迟定义

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    let a = {
    xxx: a; // a 未定义
    }
    a
    // {xxx: undefined}
    

防御型编程

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const player = {
    init: () => {
    demo.innerText = string.substr(0, n);
    demo2.innerHTML = stringDefault + string.substr(0, n);
    player.play();
    player.eventBind();
    },
    events : {
        '#btnPause': 'pause',
        '#btnPlay': 'play',
        '#btnSlow': 'slow',
        '#btnNormal': 'normal',
        '#btnFast': 'fast'
    },
    eventBind: () => {
        for(let key in player.events) {
        // 沙雕
        Object.prototype.地雷 = 1;
        console.log('key');
        console.log(key); // ...#btn... x
        const value = player.events[key]; // pause /play / slow /...
        document.querySelector(key).onclick = player[value];
        }
    },
    //...
}
  • player.events.toString player.events.valueOf等原型链上继承的方法虽然默认是不可枚举
  • 但不排除对象的原型链被沙雕加了可遍历的属性Object.prototype.x = 1,然而这是不希望被遍历到的console.log('key'+ key)
  • for in 遍历对象时会遍历到继承的属性,必须判断排除
  • hasOwnProperty判断

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    const player = {
    init: () => {
    demo.innerText = string.substr(0, n);
    demo2.innerHTML = stringDefault + string.substr(0, n);
    player.play();
    player.eventBind();
    },
    events : {
        '#btnPause': 'pause',
        '#btnPlay': 'play',
        '#btnSlow': 'slow',
        '#btnNormal': 'normal',
        '#btnFast': 'fast'
    },
    eventBind: () => {
        for(let key in player.events) {
            // 防御型编程
            if(player.events.hasOwnProperty(key)){
                const value = player.events[key]; // pause /play / slow /...
                document.querySelector(key).onclick = player[value]; // 用不同的变量去作为对象属性名
            }
        }
    },
    //...
    }
    
  • 这就属于防御型编程

另一种方法

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const player = {
    // ...
    eventBind: () => {
        /*
        for(let key in player.events) {
            // 防御型编程
            /!* 避免取到原型链上的属性 *!/
            if(player.events.hasOwnProperty(key)){
                const value = player.events[key] // pause /play / slow /...
                document.querySelector(key).onclick = player[value]
            }
        }
        */
        // 防御型编程
        Object.getOwnPropertyNames(player.events).forEach(
            (key) => {
                /* 避免取到原型链上的属性 */
                const value = player.events[key] // pause /play / slow /...
                // console.log(player.events);
                // console.log(player.events[key]);
                // console.log(typeof player.events[key]);
                document.querySelector(key).onclick = player[value]
            });
    // ...
}

目前代码的结构

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const demo = document.querySelector('#demo');
const demo2 = document.querySelector('#demo2');
let n = 1;
let intervalTime = 80;
let id;

const player = {
    init: () => { /* ... */ },
    events : { /* ... */ },
    eventBind: () => { /* ... */ },
    pause: () => { /* ... */ },
    play:() => { /* ... */ },
    slow: () => { /* ... */ },
    normal: () => { /* ... */ },
    fast: () => { /* ... */ }
};
player.init();

player对象声明和初始化以及模块化的外代码全干掉

  • n: 1,放到player里 -> player.n
  • intervalTime: 80,放到player里 -> player.intervalTime
  • id: undefined放到player里 -> player.id
  • ui放两个页面元素,表示UI界面 player.ui.demo player.ui.demo2

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    // 模块化
    import stringDefault from './stringDefault.js'
    import string from './string.js'
    import stringAnimation from './stringAnimation.js'
    
    const player = {
    id: undefined,
    n: 1,
    intervalTime: 80,
    ui: {
        demo: document.querySelector('#demo'),
        demo2: document.querySelector('#demo2')
    },
    init: () => {
        player.ui.demo.innerText = string.substr(0, player.n)
        player.ui.demo2.innerHTML = stringDefault + string.substr(0, player.n)
    player.play()
    player.eventBind()
    },
    events : {
        '#btnPause': 'pause',
        '#btnPlay': 'play',
        '#btnSlow': 'slow',
        '#btnNormal': 'normal',
        '#btnFast': 'fast'
    },
    eventBind: () => {
    /* 避免取到原型链上的属性 */
    Object.getOwnPropertyNames(player.events).forEach(
        (key) => {
            const value = player.events[key] // pause /play / slow /...
            document.querySelector(key).onclick = player[value]
        })
    },
    pause: () => {
        window.clearInterval(player.id)
    },
    run:() => {
        player.n += 1
        if(player.n > string.length){
            player.pause()
            player.ui.demo2.innerHTML += stringAnimation
            return
        }
        player.ui.demo.innerText = string.substr(0, player.n)
        player.ui.demo2.innerHTML = stringDefault + string.substr(0, player.n)
        player.ui.demo.scrollTop = player.ui.demo.scrollHeight
    },
    play:() => {
        player.pause()
        player.id = setInterval(player.run, player.intervalTime)
    },
    slow: () => {
        player.pause()
        player.intervalTime = 80
        player.play()
    },
    normal: () => {
        player.pause()
        player.intervalTime = 16
        player.play()
    },
    fast: () => {
        player.pause()
        player.intervalTime = 0
        player.play()
    }
    }
    player.init()
    

美化按钮

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总结

VSCode V.S. WebStorm

xxx.log -> console.log(xxx)


部署到 GitHub Pages

演示中,不能把<style></style>写到<body></body>里,会被parcel删掉

  • 单独保存样式到一个style.css里,就好了

.gitignore

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/node_modules/
/.cache/
/.idea
/.vscode/
/.sass-cache/

部署方式

  • 每次改完代码,必须运行这一行,才能正确的请求 JS 和 CSS:

    1
    
    parcel build src/index.html --public-url .

yarn build 一键发布

再次build的时,只需用yarn init -y 创建package.json

  • package.json中加一段脚本

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    "scripts": {
    "build":"rm -rf dist && parcel build src/index.html --no-minify --public-url ./"
    },
    

再次 yarn build


·未完待续·

参考文章

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