Realtime BPM Analyzer

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React Integration ​

How to integrate Realtime BPM Analyzer in React applications with hooks and best practices.

Live Examples ​

We've built complete React examples demonstrating different use cases. Each is a fully functional application you can interact with:

Basic File Upload ​

Upload and analyze audio files to detect their BPM.

04 React BasicLive Demo
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Full source: examples/04-react-basic

Streaming Audio ​

Analyze BPM from live audio streams or URLs.

05 React StreamingLive Demo
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Full source: examples/05-react-streaming

Microphone Input ​

Real-time BPM detection from your microphone.

06 React MicrophoneLive Demo
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View Source

Full source: examples/06-react-microphone

Installation ​

bash
npm install realtime-bpm-analyzer

Key Concepts for React ​

1. Use State for Audio Context ​

Create and store the audio context in component state to reuse it:

typescript
const [audioContext, setAudioContext] = useState<AudioContext | null>(null);
const [bpmAnalyzer, setBpmAnalyzer] = useState<BpmAnalyzer | null>(null);

2. Cleanup in useEffect ​

Always cleanup audio nodes when component unmounts:

typescript
useEffect(() => {
  return () => {
    bpmAnalyzer?.disconnect();
    audioContext?.close();
  };
}, []); // Empty deps - cleanup only on unmount

3. Handle Events with State Updates ​

Convert BPM events to React state updates:

typescript
bpmAnalyzer.on('bpmStable', (data) => {
  if (data.bpm.length > 0) {
    setCurrentBpm(data.bpm[0].tempo);
  }
});

Basic Pattern ​

Here's the essential pattern for any React integration:

typescript
import { createRealtimeBpmAnalyzer } from 'realtime-bpm-analyzer';
import { useState, useEffect } from 'react';

function BPMAnalyzer() {
  const [bpm, setBpm] = useState<number | null>(null);
  const [audioContext, setAudioContext] = useState<AudioContext | null>(null);
  const [bpmAnalyzer, setBpmAnalyzer] = useState<BpmAnalyzer | null>(null);

  const startAnalysis = async () => {
    // Create audio context
    const ctx = new AudioContext();
    setAudioContext(ctx);

    // Create analyzer
    const analyzer = await createRealtimeBpmAnalyzer(ctx);
    setBpmAnalyzer(analyzer);

    // Listen for BPM
    analyzer.on('bpmStable', (data) => {
      if (data.bpm.length > 0) {
        setBpm(data.bpm[0].tempo);
      }
    });

    // Connect your audio source here...
  };

  useEffect(() => {
    return () => {
      bpmAnalyzer?.disconnect();
      audioContext?.close();
    };
  }, []); // Cleanup only on unmount

  return (
    <div>
      <button onClick={startAnalysis}>Start Analysis</button>
      {bpm && <div>BPM: {bpm}</div>}
    </div>
  );
}

TypeScript Support ​

The library is fully typed. Import types as needed:

typescript
import type { BpmAnalyzer, BpmCandidates } from 'realtime-bpm-analyzer';

Next Steps ​