fix: Sanitize given api_host urls to not have a trailing slash

src/__tests__/posthog-core.js

@@ -702,6 +702,15 @@ describe('posthog core', () => {
             expect(given.overrides._send_request.mock.calls.length).toBe(0) // No outgoing requests
         })
 
+        it('sanitizes api_host urls', () => {
+            given('config', () => ({
+                api_host: 'https://example.com/custom/',
+            }))
+            given.subject()
+
+            expect(given.lib.config.api_host).toBe('https://example.com/custom')
+        })
+
         it('does not set __loaded_recorder_version flag if recording script has not been included', () => {
             given('overrides', () => ({
                 __loaded_recorder_version: undefined,

src/posthog-core.ts

@@ -1712,6 +1712,8 @@ export class PostHog {
                 this.config.disable_persistence = this.config.disable_cookie
             }
 
+            // We assume the api_host is without a trailing slash in most places throughout the codebase
+            this.config.api_host = this.config.api_host.replace(/\/$/, '')
             this.persistence?.update_config(this.config)
             this.sessionPersistence?.update_config(this.config)