Add a test

src/__tests__/cookieless.test.ts

@@ -0,0 +1,72 @@
+import { defaultPostHog } from './helpers/posthog-instance'
+import type { PostHogConfig } from '../types'
+import { uuidv7 } from '../uuidv7'
+
+describe('cookieless', () => {
+    const eventName = 'custom_event'
+    const eventProperties = {
+        event: 'prop',
+    }
+    const identifiedDistinctId = 'user-1'
+    const setup = (config: Partial<PostHogConfig> = {}, token: string = uuidv7()) => {
+        const beforeSendMock = jest.fn().mockImplementation((e) => e)
+        const posthog = defaultPostHog().init(token, { ...config, before_send: beforeSendMock }, token)!
+        posthog.debug()
+        return { posthog, beforeSendMock }
+    }
+
+    it('should send events with the sentinel distinct id', () => {
+        const { posthog, beforeSendMock } = setup({
+            persistence: 'memory',
+            __preview_experimental_cookieless_mode: true,
+        })
+
+        posthog.capture(eventName, eventProperties)
+        expect(beforeSendMock).toBeCalledTimes(1)
+        let event = beforeSendMock.mock.calls[0][0]
+        expect(event.properties.distinct_id).toBe('$posthog_cklsh')
+        expect(event.properties.$anon_distinct_id).toBe(undefined)
+        expect(event.properties.$device_id).toBe(null)
+        expect(event.properties.$session_id).toBe(null)
+        expect(event.properties.$window_id).toBe(null)
+        expect(event.properties.$cookieless).toEqual(true)
+        expect(document.cookie).toBe('')
+
+        // simulate user giving cookie consent
+        posthog.set_config({ persistence: 'localStorage+cookie' })
+
+        // send an event after consent
+        posthog.capture(eventName, eventProperties)
+        expect(beforeSendMock).toBeCalledTimes(2)
+        event = beforeSendMock.mock.calls[1][0]
+        expect(event.properties.distinct_id).toBe('$posthog_cklsh')
+        expect(event.properties.$anon_distinct_id).toBe(undefined)
+        expect(event.properties.$device_id).toBe(null)
+        expect(event.properties.$session_id).toBe(null)
+        expect(event.properties.$window_id).toBe(null)
+        expect(event.properties.$cookieless).toEqual(true)
+        expect(document.cookie).not.toBe('')
+
+        // a user identifying
+        posthog.identify(identifiedDistinctId)
+        expect(beforeSendMock).toBeCalledTimes(3)
+        event = beforeSendMock.mock.calls[2][0]
+        expect(event.properties.distinct_id).toBe(identifiedDistinctId)
+        expect(event.properties.$anon_distinct_id).toBe('$posthog_cklsh')
+        expect(event.properties.$device_id).toBe(null)
+        expect(event.properties.$session_id).toBe(null)
+        expect(event.properties.$window_id).toBe(null)
+        expect(event.properties.$cookieless).toEqual(true)
+
+        // an event after identifying
+        posthog.capture(eventName, eventProperties)
+        expect(beforeSendMock).toBeCalledTimes(4)
+        event = beforeSendMock.mock.calls[3][0]
+        expect(event.properties.distinct_id).toBe(identifiedDistinctId)
+        expect(event.properties.$anon_distinct_id).toBe(undefined)
+        expect(event.properties.$device_id).toBe(null)
+        expect(event.properties.$session_id).toBe(null)
+        expect(event.properties.$window_id).toBe(null)
+        expect(event.properties.$cookieless).toEqual(true)
+    })
+})

src/posthog-core.ts

@@ -508,7 +508,15 @@ export class PostHog {
             this.featureFlags.receivedFeatureFlags({ featureFlags: activeFlags, featureFlagPayloads })
         }
 
-        if (!this.get_distinct_id()) {
+        if (this.config.__preview_experimental_cookieless_mode) {
+            this.register_once(
+                {
+                    distinct_id: COOKIELESS_SENTINEL_VALUE,
+                    $device_id: null,
+                },
+                ''
+            )
+        } else if (!this.get_distinct_id()) {
             // There is no need to set the distinct id
             // or the device id if something was already stored
             // in the persistence
@@ -916,6 +924,10 @@ export class PostHog {
         let properties = { ...event_properties }
         properties['token'] = this.config.token
 
+        if (this.config.__preview_experimental_cookieless_mode) {
+            properties['$cookieless'] = true
+        }
+
         if (event_name === '$snapshot') {
             const persistenceProps = { ...this.persistence.properties(), ...this.sessionPersistence.properties() }
             properties['distinct_id'] = persistenceProps.distinct_id
@@ -2057,9 +2069,6 @@ export class PostHog {
     }
 
     private _create_device_id(): string {
-        if (this.config.__preview_experimental_cookieless_mode) {
-            return COOKIELESS_SENTINEL_VALUE
-        }
         return this.config.get_device_id(uuidv7())
     }