NRF_setAdvertising

The easiest is probably just:

function update() {
  var data = [
    analogRead(D2)*255,
    analogRead(D3)*255,
    analogRead(D4)*255,
    analogRead(D5)*255,
  ];
  NRF.setAdvertising({},{
    manufacturer:0x0590,
    manufacturerData:data
  });
}

setInterval(update, 3000);