websocket-frame-text error

[shjanken]

first, sorry for my poor English.

I write a websocket server in emacs with your awesome project.
the code is

(require 'websocket)
(eval-when-compile (require 'cl))

;;; the status of websocket-client closed
(setq ws-closed nil)

(let ((server-conn (websocket-server
		    9988
		    :Host "0.0.0.0"
		    :on-message (lambda (ws frame)
				  (message "Server received a messge")
				  (websocket-send-text
				   ws (websocket-frame-text frame)))
		    :on-open (lambda (_ws) (message "client connected open"))
		    :on-close (lambda (_ws) (setq ws-closed t))))))

and i have a client use javascript

var ws = new WebSocket('ws://localhost:9988')

ws.onopen = function() {
  ws.send("{type: 'identified', symbol: 'web'}")
};

ws.onmessage = function(event){
  console.log(event.data);
}

while(true) {
  ws.send()
}

but i received this message:

Error (websocket): in callback `on-message': Symbol's function definition is void: websocket-frame-text

please help me. Thank you very much!

[shjanken]

sorry, i think i use the wrong version.
now i install it from melpa. Everything is correct