waveform

Draw audio waveforms

Table of Contents

• waveform
  • Table of Contents
  • Installation
  • API documentation
  • Examples
  • Demos

Installation

To install, you can use npm or yarn:

$ npm install @zcool/waveform
$ yarn add @zcool/waveform

API documentation

Examples

Here is a simple example of waveform being used in an app:

import React from 'react'
import ReactDOM from 'react-dom'
import Waveform from '@zcool/waveform'

const getAudioBuffer = async path => {
  const response = await fetch(path)
  const audioData = await response.arrayBuffer()

  const context = getContext()
  return new Promise(resolve => {
    context.decodeAudioData(audioData, buffer => {
      return resolve(buffer)
    })
  })
}

/**
 * Get window audio context
 */
const getContext = () => {
  window.AudioContext =
    window.AudioContext ||
    window.webkitAudioContext ||
    window.mozAudioContext ||
    window.oAudioContext
  const context = new AudioContext()
  return context
}

function App() {
  const [waveform, setWaveform] = useState([])
  function handleChange(e) {
    const files = e.target.files
    if (files.length > 0) {
      const file = window.URL.createObjectURL(files[0])
      getAudioBuffer(file).then(buffer => {
        setWaveform(Array.from(buffer.getChannelData(0)))
        forceUpdate()
      })
    }
  }

  return (
    <div>
      <input type="file" onChange={handleChange} style={{ marginBottom: 24 }} />
      {waveform.length > 0 && <Waveform progress={0.5} data={waveform} />}
    </div>
  )
}

ReactDOM.render(<App />, appElement)

You can find more examples in the examples directory, which you can run in a local development server using npm start or yarn run start.

Demos

There are several demos hosted on CodeSandbox which demonstrate various features of @zcool/waveform:

• Minimal example