feat: allow config of before_send function to edit or reject events (#…

…1515)

cypress/e2e/before_send.cy.ts

@@ -0,0 +1,48 @@
+/// <reference types="cypress" />
+
+import { start } from '../support/setup'
+import { isArray } from '../../src/utils/type-utils'
+
+describe('before_send', () => {
+    it('can sample and edit with before_send', () => {
+        start({})
+
+        cy.posthog().then((posthog) => {
+            let counter = 0
+            const og = posthog.config.before_send
+            // cypress tests rely on existing before_send function to capture events
+            // so we have to add it back in here
+            posthog.config.before_send = [
+                (cr) => {
+                    if (cr.event === 'custom-event') {
+                        counter++
+                        if (counter === 2) {
+                            return null
+                        }
+                    }
+                    if (cr.event === '$autocapture') {
+                        return {
+                            ...cr,
+                            event: 'redacted',
+                        }
+                    }
+                    return cr
+                },
+                ...(isArray(og) ? og : [og]),
+            ]
+        })
+
+        cy.get('[data-cy-custom-event-button]').click()
+        cy.get('[data-cy-custom-event-button]').click()
+
+        cy.phCaptures().should('deep.equal', [
+            // before adding the new before sendfn
+            '$pageview',
+            'redacted',
+            'custom-event',
+            // second button click only has the redacted autocapture event
+            'redacted',
+            // because the second custom-event is rejected
+        ])
+    })
+})

cypress/support/commands.ts

@@ -9,9 +9,10 @@ Cypress.Commands.add('posthogInit', (options) => {
     cy.posthog().invoke('init', 'test_token', {
         api_host: location.origin,
         debug: true,
-        _onCapture: (event, eventData) => {
-            $captures.push(event)
-            $fullCaptures.push(eventData)
+        before_send: (event) => {
+            $captures.push(event.event)
+            $fullCaptures.push(event)
+            return event
         },
         opt_out_useragent_filter: true,
         ...options,

playground/copy-autocapture/demo.html

@@ -10,13 +10,14 @@
         loaded: function(posthog) {
             posthog.identify('test')
         },
-        _onCapture: (event, eventData) => {
-            if (event === '$copy_autocapture') {
-                const selectionType = eventData.properties['$copy_type']
-                const selectionText = eventData.properties['$selected_content']
+        before_send: (event) => {
+            if (event.event === '$copy_autocapture') {
+                const selectionType = event.properties['$copy_type']
+                const selectionText = event.properties['$selected_content']
                 document.getElementById('selection-type-outlet').innerText = selectionType
                 document.getElementById('selection-text-outlet').innerText = selectionText
             }
+            return event
         },
     })
 </script>