From ef1d6ee490f7c74f9154d929d72efb0830f8da7d Mon Sep 17 00:00:00 2001
From: dan <dan.abramov@gmail.com>
Date: Tue, 31 Oct 2023 02:07:14 +0000
Subject: [PATCH] Log time to first paint (#1775)

* Log time to first paint

* Fix TS
---
 src/Navigation.tsx | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/Navigation.tsx b/src/Navigation.tsx
index 52235ad7..a7565198 100644
--- a/src/Navigation.tsx
+++ b/src/Navigation.tsx
@@ -467,6 +467,12 @@ function RoutesContainer({children}: React.PropsWithChildren<{}>) {
       theme={theme}
       onReady={() => {
         SplashScreen.hideAsync()
+        const initMs = Math.round(
+          // @ts-ignore Emitted by Metro in the bundle prelude
+          performance.now() - global.__BUNDLE_START_TIME__,
+        )
+        console.log(`Time to first paint: ${initMs} ms`)
+
         // Register the navigation container with the Sentry instrumentation (only works on native)
         if (isNative) {
           const routingInstrumentation = getRoutingInstrumentation()