feat(cli): add env var for logging telemetry events to file

packages/@sanity/cli/src/util/createTelemetryStore.ts

@@ -1,3 +1,4 @@
+import {appendFile} from 'fs/promises'
 import {createClient, SanityClient} from '@sanity/client'
 import {ConsentStatus, createBatchedStore, createSessionId, TelemetryEvent} from '@sanity/telemetry'
 import {debug as baseDebug} from '../debug'
@@ -8,6 +9,7 @@ import {createExpiringConfig} from './createExpiringConfig'
 const debug = baseDebug.extend('telemetry')
 
 const FIVE_MINUTES = 1000 * 60 * 5
+const LOG_FILE_NAME = 'telemetry-events.ndjson'
 
 export const TELEMETRY_CONSENT_CONFIG_KEY = 'telemetryConsent'
 
@@ -57,6 +59,7 @@ function getCachedClient(token: string) {
 interface Env {
   DO_NOT_TRACK?: string
   MOCK_CONSENT?: string
+  SANITY_TELEMETRY_INSPECT?: string
 }
 
 interface Options {
@@ -147,9 +150,17 @@ export function resolveConsent({env}: Options): Promise<ConsentInformation> {
 export function createTelemetryStore<UserProperties>({env}: {env: Env}) {
   debug('Initializing telemetry')
 
+  const inspectEvents = isTrueish(env.SANITY_TELEMETRY_INSPECT)
+  if (inspectEvents) {
+    // eslint-disable-next-line no-console
+    console.info(`SANITY_TELEMETRY_INSPECT is set, appending events to "${LOG_FILE_NAME}"`)
+  }
+
   function sendEvents(entries: TelemetryEvent[]) {
     debug('Pretend submitting events:', JSON.stringify(entries))
-    return Promise.resolve()
+    return inspectEvents
+      ? appendFile(LOG_FILE_NAME, `${entries.map((entry) => JSON.stringify(entry)).join('\n')}\n`)
+      : Promise.resolve()
   }
   const sessionId = createSessionId()
   debug('session id: %s', sessionId)