Add replyPrefixer client & message option

src/structures/APIMessage.js

@@ -74,25 +74,25 @@ class APIMessage {
     const isCode = typeof this.options.code !== 'undefined' && this.options.code !== false;
     const splitOptions = isSplit ? { ...this.options.split } : undefined;
 
-    let mentionPart = '';
+    let replyPrefix = '';
     if (this.options.reply && !this.isUser && this.target.type !== 'dm') {
       const id = this.target.client.users.resolveID(this.options.reply);
-      mentionPart = `<@${this.options.reply instanceof GuildMember && this.options.reply.nickname ? '!' : ''}${id}>, `;
-      if (isSplit) {
-        splitOptions.prepend = `${mentionPart}${splitOptions.prepend || ''}`;
-      }
+      replyPrefix = this.options.replyPrefixer ? this.options.replyPrefixer(this.options.reply) :
+        this.target.client.options.replyPrefixer ? this.target.client.options.replyPrefixer(this.options.reply) :
+          `<@${this.options.reply instanceof GuildMember && this.options.reply.nickname ? '!' : ''}${id}>, `;
+      if (isSplit) splitOptions.prepend = `${replyPrefix}${splitOptions.prepend || ''}`;
     }
 
-    if (content || mentionPart) {
+    if (content || replyPrefix) {
       if (isCode) {
         const codeName = typeof this.options.code === 'string' ? this.options.code : '';
-        content = `${mentionPart}\`\`\`${codeName}\n${Util.escapeMarkdown(content, true)}\n\`\`\``;
+        content = `${replyPrefix}\`\`\`${codeName}\n${Util.escapeMarkdown(content, true)}\n\`\`\``;
         if (isSplit) {
           splitOptions.prepend = `${splitOptions.prepend || ''}\`\`\`${codeName}\n`;
           splitOptions.append = `\n\`\`\`${splitOptions.append || ''}`;
         }
-      } else if (mentionPart) {
-        content = `${mentionPart}${content}`;
+      } else if (replyPrefix) {
+        content = `${replyPrefix}${content}`;
       }
 
       const disableEveryone = typeof this.options.disableEveryone === 'undefined' ?

src/structures/interfaces/TextBasedChannel.js

@@ -62,6 +62,8 @@ class TextBasedChannel {
    * @property {boolean|SplitOptions} [split=false] Whether or not the message should be split into multiple messages if
    * it exceeds the character limit. If an object is provided, these are the options for splitting the message
    * @property {UserResolvable} [reply] User to reply to (prefixes the message with a mention, except in DMs)
+   * @property {ReplyPrefixer} [replyPrefixer] Function to override the default mention-based prefix for the reply
+   * option
    */
 
   /**

src/util/Constants.js

@@ -17,6 +17,8 @@ const browser = exports.browser = typeof window !== 'undefined';
  * @property {boolean} [fetchAllMembers=false] Whether to cache all guild members and users upon startup, as well as
  * upon joining a guild (should be avoided whenever possible)
  * @property {boolean} [disableEveryone=false] Default value for {@link MessageOptions#disableEveryone}
+ * @property {ReplyPrefixer} [replyPrefixer] Function to override the default mention-based prefix for a message
+ * reply
  * @property {number} [restWsBridgeTimeout=5000] Maximum time permitted between REST responses and their
  * corresponding websocket events
  * @property {number} [restTimeOffset=500] Extra time in millseconds to wait before continuing to make REST
@@ -41,6 +43,13 @@ exports.DefaultOptions = {
   messageSweepInterval: 0,
   fetchAllMembers: false,
   disableEveryone: false,
+  /**
+   * Function to override the default mention-based reply prefix behaviour
+   * @callback ReplyPrefixer
+   * @param {UserResolvable} user User being replied to (see {@link MessageOptions#reply})
+   * @returns {string} Prefix for the content of the reply message
+   */
+  replyPrefixer: null,
   restWsBridgeTimeout: 5000,
   disabledEvents: [],
   retryLimit: 1,

typings/index.d.ts

@@ -1575,6 +1575,7 @@ declare module 'discord.js' {
 		messageSweepInterval?: number;
 		fetchAllMembers?: boolean;
 		disableEveryone?: boolean;
+		replyPrefixer?: ReplyPrefixer;
 		restWsBridgeTimeout?: number;
 		restTimeOffset?: number;
 		retryLimit?: number,
@@ -1896,6 +1897,7 @@ declare module 'discord.js' {
 		code?: string | boolean;
 		split?: boolean | SplitOptions;
 		reply?: UserResolvable;
+		replyPrefixer?: ReplyPrefixer;
 	};
 
 	type MessageReactionResolvable = MessageReaction | Snowflake;
@@ -2006,6 +2008,8 @@ declare module 'discord.js' {
 		maxUsers?: number;
 	};
 
+	type ReplyPrefixer = (user: UserResolvable) => string;
+
 	type ResolvedOverwriteOptions = {
 		allow: Permissions;
 		deny: Permissions;