Example that does work
setTimeout((function (_this) {
    _this.logger.debug("Trying to connect to TCP");
    _this.client.connect(_this.PORT, _this.HOST, (function(_this) {
        _this.logger.info("TCP connection success on %s:%s", _this.HOST, _this.PORT);
    })(_this))
})(this), this.timeout * 1000);

Example that doesn't work
this.client.on("error", (function(_this) {
    _this.connected = false;
    _this.logger.debug("Can't connect, trying to reconnect.");
    _this.connect();
})(this));