From 09406520c4c6fe8915ebaf5caa1606a7c1e68dca Mon Sep 17 00:00:00 2001
From: Philip Walton <philip@philipwalton.com>
Date: Wed, 6 Oct 2021 16:25:13 -0700
Subject: [PATCH] Add checks to support Opera mini in presto mode

---
 rollup.config.js                | 2 +-
 src/getFCP.ts                   | 6 ++++--
 src/getFID.ts                   | 2 +-
 src/getLCP.ts                   | 8 ++++----
 src/lib/getVisibilityWatcher.ts | 4 ++--
 5 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/rollup.config.js b/rollup.config.js
index 67742ce1..ae4aef06 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -33,7 +33,7 @@ const configurePlugins = ({module, polyfill = false}) => {
     }),
     replace({
       values: {
-        'self.__WEB_VITALS_POLYFILL__': polyfill,
+        'window.__WEB_VITALS_POLYFILL__': polyfill,
       },
       preventAssignment: true,
     })
diff --git a/src/getFCP.ts b/src/getFCP.ts
index 76e3b1b2..9820898d 100644
--- a/src/getFCP.ts
+++ b/src/getFCP.ts
@@ -44,9 +44,11 @@ export const getFCP = (onReport: ReportHandler, reportAllChanges?: boolean) => {
 
   // TODO(philipwalton): remove the use of `fcpEntry` once this bug is fixed.
   // https://bugs.webkit.org/show_bug.cgi?id=225305
-  // Also, the check for `getEntriesByName` is needed to support Opera:
+  // The check for `getEntriesByName` is needed to support Opera:
   // https://github.com/GoogleChrome/web-vitals/issues/159
-  const fcpEntry = performance.getEntriesByName &&
+  // The check for `window.performance` is needed to support Opera mini:
+  // https://github.com/GoogleChrome/web-vitals/issues/185
+  const fcpEntry = window.performance && performance.getEntriesByName &&
       performance.getEntriesByName('first-contentful-paint')[0];
 
   const po = fcpEntry ? null : observe('paint', entryHandler);
diff --git a/src/getFID.ts b/src/getFID.ts
index 28c028b8..82ab3358 100644
--- a/src/getFID.ts
+++ b/src/getFID.ts
@@ -48,7 +48,7 @@ export const getFID = (onReport: ReportHandler, reportAllChanges?: boolean) => {
     }, true);
   }
 
-  if (self.__WEB_VITALS_POLYFILL__) {
+  if (window.__WEB_VITALS_POLYFILL__) {
     // Prefer the native implementation if available,
     if (!po) {
       window.webVitals.firstInputPolyfill(entryHandler as FirstInputPolyfillCallback)
diff --git a/src/getLCP.ts b/src/getLCP.ts
index f2a9a898..1df2f0f7 100644
--- a/src/getLCP.ts
+++ b/src/getLCP.ts
@@ -23,7 +23,7 @@ import {onHidden} from './lib/onHidden.js';
 import {ReportHandler} from './types.js';
 
 
-const reportedMetricIDs:Set<string> = new Set();
+const reportedMetricIDs: Record<string, boolean> = {};
 
 export const getLCP = (onReport: ReportHandler, reportAllChanges?: boolean) => {
   const visibilityWatcher = getVisibilityWatcher();
@@ -51,10 +51,10 @@ export const getLCP = (onReport: ReportHandler, reportAllChanges?: boolean) => {
     report = bindReporter(onReport, metric, reportAllChanges);
 
     const stopListening = () => {
-      if (!reportedMetricIDs.has(metric.id)) {
+      if (!reportedMetricIDs[metric.id]) {
         po.takeRecords().map(entryHandler as PerformanceEntryHandler);
         po.disconnect();
-        reportedMetricIDs.add(metric.id);
+        reportedMetricIDs[metric.id] = true;
         report(true);
       }
     }
@@ -74,7 +74,7 @@ export const getLCP = (onReport: ReportHandler, reportAllChanges?: boolean) => {
       requestAnimationFrame(() => {
         requestAnimationFrame(() => {
           metric.value = performance.now() - event.timeStamp;
-          reportedMetricIDs.add(metric.id);
+          reportedMetricIDs[metric.id] = true;
           report(true);
         });
       });
diff --git a/src/lib/getVisibilityWatcher.ts b/src/lib/getVisibilityWatcher.ts
index 9b58f8e6..fc61c858 100644
--- a/src/lib/getVisibilityWatcher.ts
+++ b/src/lib/getVisibilityWatcher.ts
@@ -36,8 +36,8 @@ export const getVisibilityWatcher = () => {
     // since navigation start. This isn't a perfect heuristic, but it's the
     // best we can do until an API is available to support querying past
     // visibilityState.
-    if (self.__WEB_VITALS_POLYFILL__) {
-      firstHiddenTime = self.webVitals.firstHiddenTime;
+    if (window.__WEB_VITALS_POLYFILL__) {
+      firstHiddenTime = window.webVitals.firstHiddenTime;
       if (firstHiddenTime === Infinity) {
         trackChanges();
       }