Help to resolve free space problem

Hi to everyone! I have trouble whith esp8266 12F FW1.91 espruino.
I send code to espruino. Code working well without errors. But if i do save(), i got error:
Too big to save to flash (13624 vs 12284 bytes)
Delete command history and try again...

(While: process.memory() = {"free": 908, "usage": 792, "total": 1700, "history": 441})
Enabled minification in ide setup is not helpful.

I use simple mqtt client sample from original documentation http://www.espruino.com/MQTT

What i do invalid? Why is not free space? How to resolve this problem?
Help please!

My code:

var server = "m13.cloudmqtt.com";
var options = {
    client_id : "test_machine",
    keep_alive: 60,
    port: 12345,
    clean_session: true,
    username: "user",
    password: "pass",
    protocol_name: "MQTT",
    protocol_level: 4,
  };
var mqtt = require("MQTT").create(server, options /*optional*/);

mqtt.connect();

mqtt.on('connected', function() {
  mqtt.subscribe("test");
});

mqtt.on('publish', function (pub) {
  console.log("topic: "+pub.topic);
  console.log("message: "+pub.message);
});

var topic = "test";
var message = 1;
setInterval('mqtt.publish(topic, message++);', 2000);

Replied to message on Gitter