taggable.js

m.prefix = "x"; // set your prefix here
const mreg = new RegExp(`^<@!?${this.client.user.id}>`);
if (mreg.test(m.content)) { // Test for a tag
  m.content = m.prefix + m.content.replace(mreg, "").replace(" ", ""); // Replaces the content of the message with the prefix instead of the tag
  m.mentions.users = m.mentions.users.filter(u => u.id != this.client.user.id); // Fixes the user tags to remove the client
  // The three lines below will change any tags with "what" and "prefix" to turn it into a "prefix" command.
  if (m.content.toLowerCase().includes("what") && m.content.toLowerCase().includes("prefix")) {
    m.content = `${m.prefix}prefix`;
  }
}
if (!m.content.startsWith(m.prefix)) return;