[soft-navigation] expose reset for cls and inp on navigation

src/attribution/onCLS.ts

@@ -86,7 +86,7 @@ export const onCLS = (
   onReport: (metric: CLSMetricWithAttribution) => void,
   opts?: ReportOpts,
 ) => {
-  unattributedOnCLS((metric: CLSMetric) => {
+  return unattributedOnCLS((metric: CLSMetric) => {
     const metricWithAttribution = attributeCLS(metric);
     onReport(metricWithAttribution);
   }, opts);

src/attribution/onINP.ts

@@ -331,7 +331,7 @@ export const onINP = (
   if (!loafObserver) {
     loafObserver = observe('long-animation-frame', handleLoAFEntries);
   }
-  unattributedOnINP((metric: INPMetric) => {
+  return unattributedOnINP((metric: INPMetric) => {
     const metricWithAttribution = attributeINP(metric);
     onReport(metricWithAttribution);
   }, opts);

src/onCLS.ts

@@ -55,16 +55,29 @@ export const onCLS = (
   // Set defaults
   opts = opts || {};
 
+  let metric = initMetric('CLS', 0);
+  let report: ReturnType<typeof bindReporter>;
+
+  let sessionValue = 0;
+  let sessionEntries: LayoutShift[] = [];
+
+  const reset = () => {
+    sessionValue = 0;
+    sessionEntries.length = 0;
+    metric = initMetric('CLS', 0);
+
+    report = bindReporter(
+      onReport,
+      metric,
+      CLSThresholds,
+      opts!.reportAllChanges,
+    );
+  };
+
   // Start monitoring FCP so we can only report CLS if FCP is also reported.
   // Note: this is done to match the current behavior of CrUX.
   onFCP(
     runOnce(() => {
-      let metric = initMetric('CLS', 0);
-      let report: ReturnType<typeof bindReporter>;
-
-      let sessionValue = 0;
-      let sessionEntries: LayoutShift[] = [];
-
       const handleEntries = (entries: LayoutShift[]) => {
         entries.forEach((entry) => {
           // Only count layout shifts without recent user input.
@@ -116,14 +129,7 @@ export const onCLS = (
         // Only report after a bfcache restore if the `PerformanceObserver`
         // successfully registered.
         onBFCacheRestore(() => {
-          sessionValue = 0;
-          metric = initMetric('CLS', 0);
-          report = bindReporter(
-            onReport,
-            metric,
-            CLSThresholds,
-            opts!.reportAllChanges,
-          );
+          reset();
 
           doubleRAF(() => report());
         });
@@ -135,4 +141,6 @@ export const onCLS = (
       }
     }),
   );
+
+  return {reset};
 };

src/onINP.ts

@@ -78,13 +78,25 @@ export const onINP = (
   // Set defaults
   opts = opts || {};
 
+  let metric = initMetric('INP');
+  let report: ReturnType<typeof bindReporter>;
+
+  const reset = () => {
+    resetInteractions();
+
+    metric = initMetric('INP');
+    report = bindReporter(
+      onReport,
+      metric,
+      INPThresholds,
+      opts!.reportAllChanges,
+    );
+  };
+
   whenActivated(() => {
     // TODO(philipwalton): remove once the polyfill is no longer needed.
     initInteractionCountPolyfill();
 
-    let metric = initMetric('INP');
-    let report: ReturnType<typeof bindReporter>;
-
     const handleEntries = (entries: INPMetric['entries']) => {
       // Queue the `handleEntries()` callback in the next idle task.
       // This is needed to increase the chances that all event entries that
@@ -147,4 +159,6 @@ export const onINP = (
       });
     }
   });
+
+  return {reset};
 };