Error with .addField Create json, or is there an easier method?

Question

Node.js

The problem is that I need the bot to get information about the user's join date, but when using this function, it gives an error that it cannot find this information. I look at popular servers and see that they added self-records later than people joined, but they get information from somewhere. Do I need to create a json file where it will write all the data, or somehow change the line? I run via cmd.

line of code:

.addField("Присоединился", moment(mbr.joinedAt).format('MMMM Do YYYY h:mm:ss'))

error code:
ReferenceError: moment is not defined

Answer 1

and moment is definitely connected?