send audio with socket io node js

var constraints = { audio: true };
navigator.mediaDevices.getUserMedia(constraints).then(function(mediaStream) {
    var mediaRecorder = new MediaRecorder(mediaStream);
    mediaRecorder.onstart = function(e) {
        this.chunks = [];
    };
    mediaRecorder.ondataavailable = function(e) {
        this.chunks.push(e.data);
    };
    mediaRecorder.onstop = function(e) {
        var blob = new Blob(this.chunks, { 'type' : 'audio/ogg; codecs=opus' });
        socket.emit('radio', blob);
    };

    // Start recording
    mediaRecorder.start();

    // Stop recording after 5 seconds and broadcast it to server
    setTimeout(function() {
        mediaRecorder.stop()
    }, 5000);
});

// When the client receives a voice message it will play the sound
socket.on('voice', function(arrayBuffer) {
    var blob = new Blob([arrayBuffer], { 'type' : 'audio/ogg; codecs=opus' });
    var audio = document.createElement('audio');
    audio.src = window.URL.createObjectURL(blob);
    audio.play();
});