record mp3 with arrayBuffer

I try a lot of things with Stackoverflow and I can't get it . So I try to record audio from raspberry pi with nodejs (1). After this stream goes through a websocket server(I don't put this code because it's just a redirection). And last a websocket in vuejs listen the stream. And after I want to record this stream in mp3 (2). But I have noise or nothing. 1 - Raspberry pi :

ai = new audio.AudioIO({
        inOptions: {
          channelCount: 1,
          sampleFormat: audio.SampleFormat16Bit,
          sampleRate: 44100,
          deviceId: 6, // Use -1 or omit the deviceId to select the default device
          closeOnError: true // Close the stream if an audio error is detected, if set false then just log the error
        }
      });

      ai.on('data', buf => {
      
      clientAudioWebsocket.send(buf)
      }
      );
      
     
      ai.start();  

2- Part vuejs

• Socket :

   this.dataBuffer = []
  
     var self = this
  
     var connectionToLocalServer = new WebSocket("ws://"+ip  +":4444")
     connectionToLocalServer.binaryType = "arraybuffer"
  
      connectionToLocalServer.onmessage = function(event) {
          self.dataBuffer.push(event.data);
  
      }
      connectionToLocalServer.onopen = function(event) {
  
  
    }
  

• part arraybuffer to mp3

    concatArrayBuffers (bufs) {
                            var offset = 0;
                            var bytes = 0;
                            var bufs2=bufs.map(function(buf,total){
                                bytes += buf.byteLength;
                                return buf;
                            });
                            var buffer = new ArrayBuffer(bytes);
                            var store = new Uint8Array(buffer);
                            bufs2.forEach(function(buf){
                                store.set(new Uint8Array(buf.buffer||buf,buf.byteOffset),offset);
                                offset += buf.byteLength;
                            });
                            return buffer }
  
  
  
            this.tmpResult = this.concatArrayBuffers(this.dataBuffer);
  
            var mp3Data = [];
  
            var mp3encoder = new lamejs.Mp3Encoder(1, 44100, 128);
  
            var mp3Tmp = mp3encoder.encodeBuffer(this.tmpResult, 0, Math.floor(this.tmpResult.byteLength / 2)); 
          //Push encode buffer to mp3Data variable
            mp3Data.push(mp3Tmp);
  
            // Get end part of mp3
            mp3Tmp = mp3encoder.flush();
  
            // Write last data to the output data, too
            // mp3Data contains now the complete mp3Data
            mp3Data.push(mp3Tmp);
  

And I don't understand why I have arraybuffer with 16384 size buffer. I'm really open to any solution, but I don't want to do it on server side. Thanks

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