1//outputs the IDs of all members with the specified role as an array
2
3// === discord.js v11 ===
4message.guild.roles.get('ROLE-ID').members.map(m=>m.user.id);
5
6// === discord.js v12 ===
7message.guild.roles.cache.get('ROLE-ID').members.map(m=>m.user.id);