title: Replace a argument with a username Discord.js
body: <p>Hey so i have been looking all over for this but can't seem to find it, I have a command that allowes users to change the welcome message on my discord bot, but I want them to be able to put in {user} and that will be replaced with the joining members username example: !setWelcomeMessage Hey {user} welcome to our server, and then the code would replace the &quot;{user}&quot; argument with member.user.username so i can use it in the bot.on('guildMemberAdd') event, please help me if you know how.</p>