简易播放器

前言

在写 JS30 11 - Custom Video Players 时遇到了做个播放器的需求，包括正常的拖拽、快进、调节音量等，记得当时用 React 仿写网抑云音乐时也写到了这个，这次用原生JS实现，顺便复习下 video 标签的一些 api 以及实现拖拽进度条。

文末有完整代码

正文

播放与暂停

const toggle = player.querySelector('.toggle');
function toggleBtn() {
    let mode, icon
    if (video.paused) {
        mode = 'play'
        icon = '❚ ❚'
    } else {
        mode = 'pause'
        icon = '►'
    }
    video[mode]()
    this.innerHTML = icon
}
toggle.addEventListener('click',toogleBtn)

video.paused 可以拿到视频的播放状态，通过其判断即可

显示进度条

function showProgress() {
    const { currentTime, duration } = video
    const percent = (currentTime / duration) * 100;
    progressBar.style.flexBasis = `${percent}%`;
}
video.addEventListener('timeupdate', showProgress);

   <div class="progress">
       <div class="progress__filled"></div>
   </div>

.progress {
  flex: 10;
  position: relative;
  display: flex;
  flex-basis: 100%;
  height: 5px;
  transition: height 0.3s;
  background: rgba(0,0,0,0.5);
  cursor: ew-resize;
}

.progress__filled {
  width: 50%;
  background: #ffc600;
  flex: 0;
  flex-basis: 50%;
}

video.currentTime和video.duration分别可以拿到当前视频的播放进度以及总时长
timeupdate事件是当currentTime更新时就会触发

页面设计中他用到了一个 flex 属性：flex-basis，其指定了 flex 元素在主轴方向上的初始大小,用(video.currentTime / video.duration) * 100 得到百分比设置即可

大部分播放器还会显示出当前时间与总时间，例如 xx:xx/yy:yy, 之前写过一个简单的函数来格式化（time单位为 s，其他情况可自行转换）

export function formatTime(time:number){
    const minute = Math.floor(time/60)
    const second = Math.floor(time%60)
    const formatMinute = minute.toString().padStart(2,'0')
    const formatSecond = second.toString().padStart(2,'0')
    return `${formatMinute}:${formatSecond}`
}

进度条拖拽

之前在写 React 时因为是数据驱动视图并且使用了 Antd 的 Slider 组件，因此写起来更方便

//  拖拽中
function handleSliding(value:number){
    setIsSliding(true)
    setProgress(value)
    const currentTime = (value/100)* duration
    setCurrentTime(currentTime)
}
//  拖拽完
function handleSlider(value:number){
    const currentTime = (value/100) * duration
    audioRef.current!.currentTime = currentTime / 1000
    setCurrentTime(currentTime)
    setProgress(value)
    setIsSliding(false)
}

<Slider
    step={0.5}
    value={progress}
    tooltip={{formatter : null}}
    onChange={handleSliding}
    onAfterChange={handleSlider}
/>

这次在写时只能手动监听长度来实现百分比,首先实现简单的点击：

function slider(e) {
  const currentTime = (e.offsetX / progress.offsetWidth) * video.duration;
  video.currentTime = currentTime;
}
progress.addEventListener('click', slider);

再进行拖动时，涉及到鼠标的一些事件,通常这三个事件可以涵括日常大部分操作

• mousedown：在定点设备（如鼠标或触摸板）按钮在元素内按下时，会在该元素上触发，其与 click 事件的区别是，click 事件在完整的单击操作完成后触发、mousedown 事件在按下鼠标按钮的那一刻触发。
• mousemove: 定点设备（通常指鼠标）的光标在元素内移动时，会在该元素上触发。
• mouseup: 在定点设备（如鼠标或触摸板）按钮在元素内释放时，在该元素上触发。

捋捋思路，鼠标按下先触发 mousedown 事件，拖动触发 mousemove 事件，再放开鼠标触发 mouseup 事件，那么代码就很清晰明了了

progress.addEventListener('mousedown', () => {
    const handleSlideWithEvent = (e) => slider(e)
    progress.addEventListener('mousemove', handleSlideWithEvent);
    progress.addEventListener('mouseup', () => {
        progress.removeEventListener('mousemove', handleSlideWithEvent);
    });
});

给的示例答案思路在这块能清晰点,使用了一个变量来阻止 mousemove 事件的持续触发

let mousedown = false;
progress.addEventListener('click', scrub);
progress.addEventListener('mousemove', (e) => mousedown && scrub(e));
progress.addEventListener('mousedown', () => mousedown = true);
progress.addEventListener('mouseup', () => mousedown = false);

快进快退

因为在 html 标签中已经通过自定义属性写了时间，故可以直接用 dataset 拿到其并直接更改 video.currentTime

<button data-skip="-10" class="player__button"><< 10s</button>
<button data-skip="25" class="player__button">25s >></button>

const skipButtons = player.querySelectorAll('[data-skip]');
function skip() {
 video.currentTime += parseInt(this.dataset.skip);
}
skipButtons.forEach(button => button.addEventListener('click', skip));

声音与倍速

同理在 html 标签中已经通过 name 属性写了要修改的属性,因为是 input 做出来的进度条，可以直接监听 change 事件，鼠标释放后才触发，再绑定 mousemove 事件，使其可以拖动时触发，elegent！

<input type="range" name="volume" class="player__slider" min="0" max="1" step="0.05" value="1">
<input type="range" name="playbackRate" class="player__slider" min="0.5" max="2" step="0.1" value="1">

function handleRangeUpdate() {
    video[this.name] = this.value;
}
ranges.forEach(range => range.addEventListener('change', handleRangeUpdate));
ranges.forEach(range => range.addEventListener('mousemove', handleRangeUpdate));

结语

挺有意思,还得是框架啊,省了一堆事(手动狗头)

完整代码

<div class="player">
    <video class="player__video viewer" src="652333414.mp4"></video>
    <div class="player__controls">
      <div class="progress">
        <div class="progress__filled"></div>
      </div>
      <button class="player__button toggle" title="Toggle Play">►</button>
      <input type="range" name="volume" class="player__slider" min="0" max="1" step="0.05" value="1">
      <input type="range" name="playbackRate" class="player__slider" min="0.5" max="2" step="0.1" value="1">
      <button data-skip="-10" class="player__button"><< 10s</button>
      <button data-skip="25" class="player__button">25s >></button>
    </div>
  </div>

html {
  box-sizing: border-box;
}

*, *:before, *:after {
  box-sizing: inherit;
}

body {
  margin: 0;
  padding: 0;
  display: flex;
  background: #7A419B;
  min-height: 100vh;
  background: linear-gradient(135deg, #7c1599 0%,#921099 48%,#7e4ae8 100%);
  background-size: cover;
  align-items: center;
  justify-content: center;
}

.player {
  max-width: 750px;
  border: 5px solid rgba(0,0,0,0.2);
  box-shadow: 0 0 20px rgba(0,0,0,0.2);
  position: relative;
  font-size: 0;
  overflow: hidden;
}

/* This css is only applied when fullscreen is active. */
.player:fullscreen {
  max-width: none;
  width: 100%;
}

.player:-webkit-full-screen {
  max-width: none;
  width: 100%;
}

.player__video {
  width: 100%;
}

.player__button {
  background: none;
  border: 0;
  line-height: 1;
  color: white;
  text-align: center;
  outline: 0;
  padding: 0;
  cursor: pointer;
  max-width: 50px;
}

.player__button:focus {
  border-color: #ffc600;
}

.player__slider {
  width: 10px;
  height: 30px;
}

.player__controls {
  display: flex;
  position: absolute;
  bottom: 0;
  width: 100%;
  transform: translateY(100%) translateY(-5px);
  transition: all .3s;
  flex-wrap: wrap;
  background: rgba(0,0,0,0.1);
}

.player:hover .player__controls {
  transform: translateY(0);
}

.player:hover .progress {
  height: 15px;
}

.player__controls > * {
  flex: 1;
}

.progress {
  flex: 10;
  position: relative;
  display: flex;
  flex-basis: 100%;
  height: 5px;
  transition: height 0.3s;
  background: rgba(0,0,0,0.5);
  cursor: ew-resize;
}

.progress__filled {
  width: 50%;
  background: #ffc600;
  flex: 0;
  flex-basis: 50%;
}

/* unholy css to style input type="range" */

input[type=range] {
  -webkit-appearance: none;
  background: transparent;
  width: 100%;
  margin: 0 5px;
}

input[type=range]:focus {
  outline: none;
}

input[type=range]::-webkit-slider-runnable-track {
  width: 100%;
  height: 8.4px;
  cursor: pointer;
  box-shadow: 1px 1px 1px rgba(0, 0, 0, 0), 0 0 1px rgba(13, 13, 13, 0);
  background: rgba(255,255,255,0.8);
  border-radius: 1.3px;
  border: 0.2px solid rgba(1, 1, 1, 0);
}

input[type=range]::-webkit-slider-thumb {
  height: 15px;
  width: 15px;
  border-radius: 50px;
  background: #ffc600;
  cursor: pointer;
  -webkit-appearance: none;
  margin-top: -3.5px;
  box-shadow:0 0 2px rgba(0,0,0,0.2);
}

input[type=range]:focus::-webkit-slider-runnable-track {
  background: #bada55;
}

input[type=range]::-moz-range-track {
  width: 100%;
  height: 8.4px;
  cursor: pointer;
  box-shadow: 1px 1px 1px rgba(0, 0, 0, 0), 0 0 1px rgba(13, 13, 13, 0);
  background: #ffffff;
  border-radius: 1.3px;
  border: 0.2px solid rgba(1, 1, 1, 0);
}

input[type=range]::-moz-range-thumb {
  box-shadow: 0 0 0 rgba(0, 0, 0, 0), 0 0 0 rgba(13, 13, 13, 0);
  height: 15px;
  width: 15px;
  border-radius: 50px;
  background: #ffc600;
  cursor: pointer;
}

const player = document.querySelector('.player');
const video = player.querySelector('.viewer');
const progress = player.querySelector('.progress');
const progressBar = player.querySelector('.progress__filled');
const toggle = player.querySelector('.toggle');
const skipButtons = player.querySelectorAll('[data-skip]');
const ranges = player.querySelectorAll('.player__slider');

function toggleBtn() {
    let mode, icon
    if (video.paused) {
        mode = 'play'
        icon = '❚ ❚'
    } else {
        mode = 'pause'
        icon = '►'
    }
    video[mode]()
    this.innerHTML = icon
}
function skip() {
    video.currentTime += parseInt(this.dataset.skip);
}

function showProgress() {
    const { currentTime, duration } = video
    console.log(`${formatTime(currentTime)}/${formatTime(duration)}`)
    const percent = (currentTime / duration) * 100;
    progressBar.style.flexBasis = `${percent}%`;
}

function formatTime(time) {
    const minute = Math.floor(time / 60)
    const second = Math.floor(time % 60)
    const formatMinute = minute.toString().padStart(2, '0')
    const formatSecond = second.toString().padStart(2, '0')
    return `${formatMinute}:${formatSecond}`
}

function slider(e) {
    const currentTime = (e.offsetX / progress.offsetWidth) * video.duration;
    video.currentTime = currentTime;
}

function handleRangeUpdate() {
    video[this.name] = this.value;
}


toggle.addEventListener('click', toggleBtn)

video.addEventListener('timeupdate', showProgress);
progress.addEventListener('click', slider);

progress.addEventListener('mousedown', () => {
    const handleSlideWithEvent = (e) => slider(e)
    progress.addEventListener('mousemove', handleSlideWithEvent);
    progress.addEventListener('mouseup', () => {
        progress.removeEventListener('mousemove', handleSlideWithEvent);
    });
});

skipButtons.forEach(button => button.addEventListener('click', skip));

ranges.forEach(range => range.addEventListener('change', handleRangeUpdate));
ranges.forEach(range => range.addEventListener('mousemove', handleRangeUpdate));