Stop posthog-js downloading surveys.js on every page

apps/website/instrumentation-client.spec.ts

@@ -24,9 +24,17 @@ describe('website posthog init options', () => {
       autocapture: true,
       capture_performance: { web_vitals: true },
       person_profiles: 'always',
+      disable_surveys: true,
     });
   });
 
+  // Named for the same reason as the capture_pageview case below: the project's
+  // remote `surveys: false` does not stop posthog-js downloading surveys.js,
+  // so dropping this flag silently restores a 33.5KB fetch on every page.
+  it('keeps the surveys bundle from loading at all', () => {
+    expect(POSTHOG_INIT_OPTIONS.disable_surveys).toBe(true);
+  });
+
   // Redundant with the toEqual above, deliberately: this IS the bug this fix
   // exists for, and a named failure here is far more legible than an object
   // diff. Do not "simplify" this away.

apps/website/instrumentation-client.ts

@@ -37,6 +37,16 @@ export const POSTHOG_INIT_OPTIONS = {
   autocapture: true,
   capture_performance: { web_vitals: true },
   person_profiles: 'always',
+  /*
+   * The site runs no surveys, and the project's remote config already says
+   * `surveys: false` — but that does NOT stop the 33.5KB `surveys.js` download.
+   * posthog-js loads the extension once the remote value has ARRIVED, whatever
+   * it is (`if (!isUndefined(remoteSurveys) || advanced_enable_surveys)`), then
+   * does nothing with it. Only this client flag is checked before that load, so
+   * the project setting alone can never prevent it. Measured on production with
+   * mobile throttling, the bundle arrived at ~4.9s on every page.
+   */
+  disable_surveys: true,
 } satisfies Partial<PostHogConfig>;
 
 if (shouldCaptureAnalytics({ token, captureLocal, host: browserHost })) {