How to Build an Audio Player with Claude Code

Building an Audio Player with Claude Code

There are many situations where you need a custom audio player: music streaming services, podcasts, educational content, and more. With Claude Code, you can build a full-featured player with waveform visualization and a playlist.

Implementing the Base Player

> Build a custom audio player.
> Support play/pause, a seek bar, volume, and playback speed.
> Also implement a playlist and waveform display.

// src/components/AudioPlayer.tsx
'use client';
import { useRef, useState, useEffect } from 'react';

interface Track {
  id: string;
  title: string;
  artist: string;
  src: string;
  duration: number;
  coverArt?: string;
}

interface AudioPlayerProps {
  tracks: Track[];
  initialTrackIndex?: number;
}

export function AudioPlayer({ tracks, initialTrackIndex = 0 }: AudioPlayerProps) {
  const audioRef = useRef<HTMLAudioElement>(null);
  const [currentTrackIndex, setCurrentTrackIndex] = useState(initialTrackIndex);
  const [isPlaying, setIsPlaying] = useState(false);
  const [currentTime, setCurrentTime] = useState(0);
  const [duration, setDuration] = useState(0);
  const [volume, setVolume] = useState(0.8);

  const currentTrack = tracks[currentTrackIndex];

  useEffect(() => {
    const audio = audioRef.current;
    if (!audio) return;

    const onTimeUpdate = () => setCurrentTime(audio.currentTime);
    const onLoadedMetadata = () => setDuration(audio.duration);
    const onEnded = () => playNext();

    audio.addEventListener('timeupdate', onTimeUpdate);
    audio.addEventListener('loadedmetadata', onLoadedMetadata);
    audio.addEventListener('ended', onEnded);

    return () => {
      audio.removeEventListener('timeupdate', onTimeUpdate);
      audio.removeEventListener('loadedmetadata', onLoadedMetadata);
      audio.removeEventListener('ended', onEnded);
    };
  }, [currentTrackIndex]);

  const togglePlay = () => {
    const audio = audioRef.current;
    if (!audio) return;
    if (audio.paused) {
      audio.play();
      setIsPlaying(true);
    } else {
      audio.pause();
      setIsPlaying(false);
    }
  };

  const playNext = () => {
    const nextIndex = (currentTrackIndex + 1) % tracks.length;
    setCurrentTrackIndex(nextIndex);
    setTimeout(() => {
      audioRef.current?.play();
      setIsPlaying(true);
    }, 100);
  };

  const playPrevious = () => {
    if (currentTime > 3) {
      // If more than 3 seconds have elapsed, restart the track
      audioRef.current!.currentTime = 0;
    } else {
      const prevIndex = (currentTrackIndex - 1 + tracks.length) % tracks.length;
      setCurrentTrackIndex(prevIndex);
      setTimeout(() => {
        audioRef.current?.play();
        setIsPlaying(true);
      }, 100);
    }
  };

  const formatTime = (sec: number) => {
    const m = Math.floor(sec / 60);
    const s = Math.floor(sec % 60);
    return `${m}:${s.toString().padStart(2, '0')}`;
  };

  return (
    <div className="bg-white dark:bg-gray-800 rounded-2xl shadow-lg overflow-hidden max-w-md mx-auto">
      <audio ref={audioRef} src={currentTrack.src} preload="metadata" />

      {/* Cover art */}
      <div className="aspect-square bg-gray-200 dark:bg-gray-700 relative">
        {currentTrack.coverArt ? (
          <img src={currentTrack.coverArt} alt={currentTrack.title} className="w-full h-full object-cover" />
        ) : (
          <div className="w-full h-full flex items-center justify-center text-6xl text-gray-400">♪</div>
        )}
      </div>

      {/* Track info */}
      <div className="p-6">
        <h3 className="text-lg font-bold dark:text-white truncate">{currentTrack.title}</h3>
        <p className="text-gray-500 dark:text-gray-400 text-sm">{currentTrack.artist}</p>

        {/* Seek bar */}
        <div className="mt-4">
          <input
            type="range"
            min={0}
            max={duration || 0}
            value={currentTime}
            onChange={(e) => {
              const time = Number(e.target.value);
              audioRef.current!.currentTime = time;
              setCurrentTime(time);
            }}
            className="w-full h-1 accent-blue-600"
          />
          <div className="flex justify-between text-xs text-gray-400 mt-1">
            <span>{formatTime(currentTime)}</span>
            <span>{formatTime(duration)}</span>
          </div>
        </div>

        {/* Controls */}
        <div className="flex items-center justify-center gap-6 mt-4">
          <button onClick={playPrevious} className="text-2xl dark:text-white hover:text-blue-600">⏮</button>
          <button
            onClick={togglePlay}
            className="w-14 h-14 rounded-full bg-blue-600 text-white text-2xl flex items-center justify-center hover:bg-blue-700"
          >
            {isPlaying ? '⏸' : '▶'}
          </button>
          <button onClick={playNext} className="text-2xl dark:text-white hover:text-blue-600">⏭</button>
        </div>

        {/* Volume */}
        <div className="flex items-center gap-2 mt-4">
          <span className="text-sm dark:text-gray-400">🔊</span>
          <input
            type="range"
            min={0}
            max={1}
            step={0.05}
            value={volume}
            onChange={(e) => {
              const vol = Number(e.target.value);
              audioRef.current!.volume = vol;
              setVolume(vol);
            }}
            className="flex-1 h-1 accent-blue-600"
          />
        </div>
      </div>

      {/* Playlist */}
      <div className="border-t dark:border-gray-700 max-h-60 overflow-y-auto">
        {tracks.map((track, index) => (
          <button
            key={track.id}
            onClick={() => {
              setCurrentTrackIndex(index);
              setTimeout(() => { audioRef.current?.play(); setIsPlaying(true); }, 100);
            }}
            className={`w-full flex items-center gap-3 p-3 text-left hover:bg-gray-50 dark:hover:bg-gray-700 ${
              index === currentTrackIndex ? 'bg-blue-50 dark:bg-blue-900/30' : ''
            }`}
          >
            <span className="text-xs text-gray-400 w-6 text-right">
              {index === currentTrackIndex && isPlaying ? '♪' : index + 1}
            </span>
            <div className="flex-1 min-w-0">
              <p className="text-sm font-medium dark:text-white truncate">{track.title}</p>
              <p className="text-xs text-gray-500 truncate">{track.artist}</p>
            </div>
            <span className="text-xs text-gray-400">{formatTime(track.duration)}</span>
          </button>
        ))}
      </div>
    </div>
  );
}

Waveform Display with the Web Audio API

For a more advanced feature, you can also ask Claude Code to implement real-time waveform visualization using the Web Audio API. Combining AudioContext and AnalyserNode lets you render the playing audio’s waveform onto a canvas.

Related Articles

For video player implementation, see the video player build guide, and for responsive behavior, see responsive design.

For more on the Web Audio API, see MDN (developer.mozilla.org/Web/API/Web_Audio_API).