snapshot of https://github.com/RocketChat/Rocket.Chat.git (develop, 2026-09-16; blobs > 131072B omitted)

apps/meteor/server/lib/messages/extractMentionsFromMessageAST.ts

@@ -0,0 +1,63 @@
+import type { Root, Paragraph, Blocks, Inlines, UserMention, ChannelMention, Task, ListItem, BigEmoji } from '@rocket.chat/message-parser';
+
+type ExtractedMentions = {
+	mentions: string[];
+	channels: string[];
+};
+
+type MessageNode = Paragraph | Blocks | Inlines | Task | ListItem | BigEmoji;
+
+function isUserMention(node: MessageNode): node is UserMention {
+	return node.type === 'MENTION_USER';
+}
+
+function isChannelMention(node: MessageNode): node is ChannelMention {
+	return node.type === 'MENTION_CHANNEL';
+}
+
+function hasArrayValue(node: MessageNode): node is MessageNode & { value: MessageNode[] } {
+	return Array.isArray(node.value);
+}
+
+function hasObjectValue(node: MessageNode): node is MessageNode & { value: Record<string, MessageNode> } {
+	return typeof node.value === 'object' && node.value !== null && !Array.isArray(node.value);
+}
+
+function traverse(node: MessageNode, mentions: Set<string>, channels: Set<string>): void {
+	if (isUserMention(node)) {
+		mentions.add(node.value.value);
+		return;
+	}
+
+	if (isChannelMention(node)) {
+		channels.add(node.value.value);
+		return;
+	}
+
+	if (hasArrayValue(node)) {
+		for (const child of node.value) {
+			traverse(child, mentions, channels);
+		}
+		return;
+	}
+
+	if (hasObjectValue(node)) {
+		for (const key of Object.keys(node.value)) {
+			traverse(node.value[key], mentions, channels);
+		}
+	}
+}
+
+export function extractMentionsFromMessageAST(ast: Root): ExtractedMentions {
+	const mentions = new Set<string>();
+	const channels = new Set<string>();
+
+	for (const node of ast) {
+		traverse(node, mentions, channels);
+	}
+
+	return {
+		mentions: Array.from(mentions),
+		channels: Array.from(channels),
+	};
+}