Add workaround for Safari FCP bug

GoogleChrome · May 4, 2021 · 4dfde19 · 4dfde19
1 parent 78b2bf4
commit 4dfde19
Showing 1 changed file with 10 additions and 2 deletions.
diff --git a/src/getFCP.ts b/src/getFCP.ts
@@ -44,10 +44,18 @@ export const getFCP = (onReport: ReportHandler, reportAllChanges?: boolean) => {
     }
   };
 
-  const po = observe('paint', entryHandler);
-  if (po) {
+  // TODO(philipwalton): remove the use of `fcpEntry` once this bug is fixed.
+  // https://bugs.webkit.org/show_bug.cgi?id=225305
+  const fcpEntry = performance.getEntriesByName('first-contentful-paint')[0];
+  const po = fcpEntry ? null : observe('paint', entryHandler);
+
+  if (fcpEntry || po) {
     report = bindReporter(onReport, metric, reportAllChanges);
 
+    if (fcpEntry) {
+      entryHandler(fcpEntry);
+    }
+
     onBFCacheRestore((event) => {
       metric = initMetric('FCP');
       report = bindReporter(onReport, metric, reportAllChanges);