Js fetch API always returns undefined[resolved]

Question

I am creating a chatbot on a website. In it the client side code uses fetch api to obtain reply from chatbot on a server. However it always returns undefined.
Here is the server side snippet(flask python):
@app.route("/rep/<input>")
def rep(input):
return jsonify(reply=ai_reply(input))

Here is the client side code:
https://www.pythonanywhere.com/user/pbkdev/shares/d9468a10cb134611bd5f600d65180095/

What is the error please help?
https://code.sololearn.com/WNDKG05Z731I/?ref=app

Answer 1

You need to provide a full URL
'/rep/'+input will not work.

See example
https://code.sololearn.com/WUN219pVaXPX/#html

Answer 2

My server log shows the request is being processed and the response is being sent back. That is a relative url and it will work for intrawebsite requests