static async decode()

in 9-realtime/openai-realtime-console-example/src/lib/wavtools/lib/wav_recorder.js [63:130]
68 lines of code
12 McCabe index (conditional complexity)

  static async decode(audioData, sampleRate = 44100, fromSampleRate = -1) {
    const context = new AudioContext({ sampleRate });
    let arrayBuffer;
    let blob;
    if (audioData instanceof Blob) {
      if (fromSampleRate !== -1) {
        throw new Error(
          `Can not specify "fromSampleRate" when reading from Blob`,
        );
      }
      blob = audioData;
      arrayBuffer = await blob.arrayBuffer();
    } else if (audioData instanceof ArrayBuffer) {
      if (fromSampleRate !== -1) {
        throw new Error(
          `Can not specify "fromSampleRate" when reading from ArrayBuffer`,
        );
      }
      arrayBuffer = audioData;
      blob = new Blob([arrayBuffer], { type: 'audio/wav' });
    } else {
      let float32Array;
      let data;
      if (audioData instanceof Int16Array) {
        data = audioData;
        float32Array = new Float32Array(audioData.length);
        for (let i = 0; i < audioData.length; i++) {
          float32Array[i] = audioData[i] / 0x8000;
        }
      } else if (audioData instanceof Float32Array) {
        float32Array = audioData;
      } else if (audioData instanceof Array) {
        float32Array = new Float32Array(audioData);
      } else {
        throw new Error(
          `"audioData" must be one of: Blob, Float32Arrray, Int16Array, ArrayBuffer, Array<number>`,
        );
      }
      if (fromSampleRate === -1) {
        throw new Error(
          `Must specify "fromSampleRate" when reading from Float32Array, In16Array or Array`,
        );
      } else if (fromSampleRate < 3000) {
        throw new Error(`Minimum "fromSampleRate" is 3000 (3kHz)`);
      }
      if (!data) {
        data = WavPacker.floatTo16BitPCM(float32Array);
      }
      const audio = {
        bitsPerSample: 16,
        channels: [float32Array],
        data,
      };
      const packer = new WavPacker();
      const result = packer.pack(fromSampleRate, audio);
      blob = result.blob;
      arrayBuffer = await blob.arrayBuffer();
    }
    const audioBuffer = await context.decodeAudioData(arrayBuffer);
    const values = audioBuffer.getChannelData(0);
    const url = URL.createObjectURL(blob);
    return {
      blob,
      url,
      values,
      audioBuffer,
    };
  }