Custom video player

This is the eleventh project of Wes Bos's JS30 series. To see the whole 30 part series, click here We'll be building our own custom video player.

Here is the video

And here are the starter files

Again, in this project we won't be touching the HTML or CSS, but we need to understand the html structure.

<div class="player">
     <video class="player__video viewer" src="https://player.vimeo.com/external/194837908.sd.mp4?s=c350076905b78c67f74d7ee39fdb4fef01d12420&profile_id=164"></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>

The player is contained in div.player, the video comes from the <video> element, the controls are under div.player__controls. The animation you see when hovering on the video is a combination of CSS transition and transform.

Features of the player include - play/pause the video, skip forward/backward, adjust speed, adjust volume, display progress and seek position in video.

Main steps involved in creating the player :

1. Get a reference to all the elements we need to control
2. Write a function to play/pause
3. Update the play/pause button based on state of video
4. Add the skip forward and backward functionality
5. Handle the volume change
6. Handle the playback speed range
7. Display the video progress
8. Seek a position in the video by clicking/dragging on the progress bar

Get all the elements

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');

You can read more about the video element or preferably the Media element it inherits from. We'll be using the JS properties quite a bit. If you also fancy a tutorial about the video element html5rocks has a brilliant one!

Write a function to play/pause

function togglePlay() {
  if(video.paused) video.play();
  else video.pause();
}

// You can toggle either by clicking the video or the play/pause button
video.addEventListener('click', togglePlay);
toggle.addEventListener('click', togglePlay);

This function checks if the video is paused, if so it starts playing it, if not it pauses the playing video. For all the properties and function relating to the video element, please refer to the links to the docs/tutorials I've mentioned above.

Update the play/pause button

function updateButton() {
  const icon = this.paused ? '►' : '❚❚';
  toggle.textContent = icon;
}

video.addEventListener('play', updateButton);
video.addEventListener('pause', updateButton);

The video can be paused / played by other means than clicking on the video / toggle button. So instead of adding the logic in the togglePlay we'll listen to the 'play' and 'pause' events on the video element.

Add the skip forward and backward functionality

function skip() {
 video.currentTime += parseFloat(this.dataset.skip);
}

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

We can change the video time by assigning the new time to video.currentTime. The skip time is got from the data-skip attribute. So you can go -10 seconds back in time or skip 25 seconds ahead.

Handle the volume and playback rate change

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

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

Here we exploit the fact that both volume and range playback are slider elements. video.volume and video.playbackRate control the volume and playback speed respectively. The elements name coincides with the property of the video object.

<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">

Hence we can just use video[this.name], it will resolve to either video.volume or video.playbackRate based on which element we're sliding. Assigning to this.value remains same anyway. This way we don't have to duplicate the code!

Display the video progress

function handleProgress() {
  const percent = (video.currentTime / video.duration) * 100;
  progressBar.style.flexBasis = `${percent}%`;
}

video.addEventListener('timeupdate', handleProgress);

The yellow bar shows the % of the video that has completed. We attach a 'timeupdate' event listener to the video element, every time it fires the percent is calculated and the progressBar's CSS flexBasis property is set!

Seek a position in the video

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

progress.addEventListener('click', scrub);

We get from the click event the relative position where the mouse was clicked, then calculate the % width and get the scrubTime from that.

Now to enable dragging as well

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

If the mouse is down and we move the mouse over the progress bar, scrub is triggered and the target position is seeked!

That is all for making your own minimalistic custom video player! Here is the final code