How can I listen the WIZnet module and catch its errors?

I use a module WIZnet W5500 for network.
My code:

let WIZnet = require("WIZnet");
var http = require("http");
SPI2.setup({mosi: B15, miso: B14, sck: B13});
let eth = WIZnet.connect(SPI2, B12);
setTimeout(function() {
  eth.setIP();
  console.log("ip", eth.getIP());
},1000);

If I unplug the net cable, this code stopped in 'ERROR: No free sockets found', but I don't know how to catch this error.

On the other hand, how do I continuedly listen the eth while I plug the net cable for initializing the network?