function buildWaveHeader()

in src/index.js [305:351]

• 26 lines of code
• 4 McCabe index (conditional complexity)

function buildWaveHeader(opts) {
  var numFrames = opts.numFrames;
  var numChannels = opts.numChannels || 2;
  var sampleRate = opts.sampleRate || 44100;
  var bytesPerSample = opts.bytesPerSample || 2;
  var blockAlign = numChannels * bytesPerSample;
  var byteRate = sampleRate * blockAlign;
  var dataSize = numFrames * blockAlign;

  var buffer = new ArrayBuffer(44);
  var dv = new DataView(buffer);

  var p = 0;

  function writeString(s) {
    for (var i = 0; i < s.length; i++) {
      dv.setUint8(p + i, s.charCodeAt(i));
    }
    p += s.length;
  }

  function writeUint32(d) {
    dv.setUint32(p, d, true);
    p += 4;
  }

  function writeUint16(d) {
    dv.setUint16(p, d, true);
    p += 2;
  }

  writeString('RIFF');              // ChunkID
  writeUint32(dataSize + 36);       // ChunkSize
  writeString('WAVE');              // Format
  writeString('fmt ');              // Subchunk1ID
  writeUint32(16);                  // Subchunk1Size
  writeUint16(1);                   // AudioFormat
  writeUint16(numChannels);         // NumChannels
  writeUint32(sampleRate);          // SampleRate
  writeUint32(byteRate);            // ByteRate
  writeUint16(blockAlign);          // BlockAlign
  writeUint16(bytesPerSample * 8);  // BitsPerSample
  writeString('data');              // Subchunk2ID
  writeUint32(dataSize);            // Subchunk2Size

  return buffer;
}