[web] add analytics for @mentions (#36144)

GitOrigin-RevId: 9fb1447166eb5ee82867466abc9af2207c886f8b

services/web/frontend/js/features/review-panel/context/threads-context.tsx

@@ -35,6 +35,7 @@ import { useCodeMirrorViewContext } from '@/features/source-editor/components/co
 import { rangesUpdatedEffect } from '@/features/source-editor/extensions/history-ot'
 import { useEditorAnalytics } from '@/shared/hooks/use-editor-analytics'
 import { useReviewPanelViewContext } from './review-panel-view-context'
+import { countMentionedUsers } from '@/shared/utils/parse-mentions'
 
 export type Threads = Record<ThreadId, ReviewPanelCommentThread>
 
@@ -279,7 +280,10 @@ export const ThreadsProvider: FC<React.PropsWithChildren> = ({ children }) => {
           body: { content },
         })
 
-        sendEvent('rp-new-comment', { size: content.length })
+        sendEvent('rp-new-comment', {
+          size: content.length,
+          'mentions-count': countMentionedUsers(content),
+        })
 
         const op: CommentOperation = {
           c: text,
@@ -317,6 +321,7 @@ export const ThreadsProvider: FC<React.PropsWithChildren> = ({ children }) => {
           view: reviewPanelView,
           size: content.length,
           thread: threadId,
+          'mentions-count': countMentionedUsers(content),
         })
       },
       async editMessage(
@@ -351,7 +356,10 @@ export const ThreadsProvider: FC<React.PropsWithChildren> = ({ children }) => {
             body: { content },
           })
 
-          sendEvent('rp-new-comment', { size: content.length })
+          sendEvent('rp-new-comment', {
+            size: content.length,
+            'mentions-count': countMentionedUsers(content),
+          })
 
           const trackedDeletes = trackedDeletesFromState(view.state)
           pos = trackedDeletes.toSnapshot(pos)

services/web/frontend/js/shared/utils/parse-mentions.ts

@@ -29,6 +29,16 @@ export function parseMentions(content: string): MentionSegment[] {
   return segments
 }
 
+export function countMentionedUsers(content: string): number {
+  const userIds = new Set<string>()
+
+  for (const match of content.matchAll(MENTION_REGEX)) {
+    userIds.add(match[1])
+  }
+
+  return userIds.size
+}
+
 const MENTION_RAW_LENGTH = 27 // @[ + 24 hex chars + ]
 
 export function sliceMentionSegments(

services/web/test/frontend/shared/utils/parse-mentions.test.ts

@@ -1,5 +1,6 @@
 import { expect } from 'chai'
 import {
+  countMentionedUsers,
   parseMentions,
   sliceMentionSegments,
 } from '@/shared/utils/parse-mentions'
@@ -76,6 +77,33 @@ describe('parseMentions', function () {
   })
 })
 
+describe('countMentionedUsers', function () {
+  const userId1 = 'aabbccddeeff00112233aabb' as UserId
+  const userId2 = '112233445566778899aabbcc' as UserId
+
+  it('should return 0 for content without mentions', function () {
+    expect(countMentionedUsers('hello world')).to.equal(0)
+  })
+
+  it('should count a single mention', function () {
+    expect(countMentionedUsers(`hey @[${userId1}]`)).to.equal(1)
+  })
+
+  it('should count distinct mentioned users', function () {
+    expect(countMentionedUsers(`@[${userId1}] and @[${userId2}]`)).to.equal(2)
+  })
+
+  it('should count a repeated user only once', function () {
+    expect(countMentionedUsers(`@[${userId1}] @[${userId1}]`)).to.equal(1)
+  })
+
+  it('should ignore malformed mentions', function () {
+    expect(countMentionedUsers('@[aabbcc] @aabbccddeeff00112233aabb')).to.equal(
+      0
+    )
+  })
+})
+
 describe('sliceMentionSegments', function () {
   const userId = 'aabbccddeeff00112233aabb' as UserId