How to get the member's nickname in a guild?

[zebia13]

Using message.author.username I have the discord username, but it's different from the nickname the user has in the guild where he send the message.

A discord user, with James as username, but with Alison as nickname in the guild send the message :
!hello bot

a code with :

message.reply(` hello ${message.author.username}!`

will result with :
Alison hello James!

How to have the result :
Alison hello Alison!

Using only ${message.author} works in this case, but in an embed message, it cause a bug, you have the member's id and not the nickname.

[almostSouji]

Nickname is guild bound data, as such available on the GuildMember instance.
The GuildMember for the message author can be accessed via <Message>.member.

.toString() called on a User will yield the mention format <@id> (template literals implicitly call .toString() to display a value).
.valueOf() called on a User will yield its id (string) (any other concatenation implicitly calls .valueOf())

[nottizii]

You can use <Member>.displayName