The bot does not understand roles.add, what should I do?

Question

Node.js

Line: message.author.roles.add("737598576124756018")
Tried by any means, followed discord.js methods, does not help.
I need the post author to be given a role with id 737598576124756018
I would be very grateful if I could get any help!! Very important!!

Error: TypeError: Cannot read property 'add' of undefined

Answer 1

the author property is of the class type User , which at one time represents a discord user , not a server member .
if you want to work with a server member , you must use the member property , which is of class type GuildMember .

Answer 2

Try

message.author.roles.cache.add("737598576124756018");