Add eventListener to reset CLS & INP metrics

src/lib/manualSoftNavigation.ts

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export const onManualSoftNavigation = (cb: () => void) => {
+  document.addEventListener('reset-web-vital-metrics', cb);
+};

src/onCLS.ts

@@ -28,6 +28,7 @@ import {
   MetricRatingThresholds,
   ReportOpts,
 } from './types.js';
+import {onManualSoftNavigation} from './lib/manualSoftNavigation.js';
 
 /** Thresholds for CLS. See https://web.dev/articles/cls#what_is_a_good_cls_score */
 export const CLSThresholds: MetricRatingThresholds = [0.1, 0.25];
@@ -115,9 +116,7 @@ export const onCLS = (onReport: CLSReportCallback, opts?: ReportOpts) => {
           report(true);
         });
 
-        // Only report after a bfcache restore if the `PerformanceObserver`
-        // successfully registered.
-        onBFCacheRestore(() => {
+        const resetCLSMetric = () => {
           sessionValue = 0;
           metric = initMetric('CLS', 0);
           report = bindReporter(
@@ -126,10 +125,20 @@ export const onCLS = (onReport: CLSReportCallback, opts?: ReportOpts) => {
             CLSThresholds,
             opts!.reportAllChanges,
           );
+        };
 
+        // Only report after a bfcache restore if the `PerformanceObserver`
+        // successfully registered.
+        onBFCacheRestore(() => {
+          resetCLSMetric();
           doubleRAF(() => report());
         });
 
+        onManualSoftNavigation(() => {
+          report(true);
+          resetCLSMetric();
+        });
+
         // Queue a task to report (if nothing else triggers a report first).
         // This allows CLS to be reported as soon as FCP fires when
         // `reportAllChanges` is true.

src/onINP.ts

@@ -17,6 +17,7 @@
 import {onBFCacheRestore} from './lib/bfcache.js';
 import {bindReporter} from './lib/bindReporter.js';
 import {initMetric} from './lib/initMetric.js';
+import {onManualSoftNavigation} from './lib/manualSoftNavigation.js';
 import {observe} from './lib/observe.js';
 import {onHidden} from './lib/onHidden.js';
 import {
@@ -240,21 +241,28 @@ export const onINP = (onReport: INPReportCallback, opts?: ReportOpts) => {
         report(true);
       });
 
-      // Only report after a bfcache restore if the `PerformanceObserver`
-      // successfully registered.
-      onBFCacheRestore(() => {
+      const resetINPMetric = () => {
         longestInteractionList = [];
-        // Important, we want the count for the full page here,
-        // not just for the current navigation.
         prevInteractionCount = getInteractionCount();
-
         metric = initMetric('INP');
+
         report = bindReporter(
           onReport,
           metric,
           INPThresholds,
           opts!.reportAllChanges,
         );
+      };
+
+      // Only report after a bfcache restore if the `PerformanceObserver`
+      // successfully registered.
+      onBFCacheRestore(() => {
+        resetINPMetric();
+      });
+
+      onManualSoftNavigation(() => {
+        report(true);
+        resetINPMetric();
       });
     }
   });