Initial Commit

node_modules/web-vitals/dist/modules/lib/interactions.js

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+/*
+ * Copyright 2024 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.
+ */
+import { getInteractionCount } from './polyfills/interactionCountPolyfill.js';
+// A list of longest interactions on the page (by latency) sorted so the
+// longest one is first. The list is at most MAX_INTERACTIONS_TO_CONSIDER long.
+export const longestInteractionList = [];
+// A mapping of longest interactions by their interaction ID.
+// This is used for faster lookup.
+export const longestInteractionMap = new Map();
+// The default `durationThreshold` used across this library for observing
+// `event` entries via PerformanceObserver.
+export const DEFAULT_DURATION_THRESHOLD = 40;
+// Used to store the interaction count after a bfcache restore, since p98
+// interaction latencies should only consider the current navigation.
+let prevInteractionCount = 0;
+/**
+ * Returns the interaction count since the last bfcache restore (or for the
+ * full page lifecycle if there were no bfcache restores).
+ */
+const getInteractionCountForNavigation = () => {
+    return getInteractionCount() - prevInteractionCount;
+};
+export const resetInteractions = () => {
+    prevInteractionCount = getInteractionCount();
+    longestInteractionList.length = 0;
+    longestInteractionMap.clear();
+};
+/**
+ * Returns the estimated p98 longest interaction based on the stored
+ * interaction candidates and the interaction count for the current page.
+ */
+export const estimateP98LongestInteraction = () => {
+    const candidateInteractionIndex = Math.min(longestInteractionList.length - 1, Math.floor(getInteractionCountForNavigation() / 50));
+    return longestInteractionList[candidateInteractionIndex];
+};
+// To prevent unnecessary memory usage on pages with lots of interactions,
+// store at most 10 of the longest interactions to consider as INP candidates.
+const MAX_INTERACTIONS_TO_CONSIDER = 10;
+/**
+ * A list of callback functions to run before each entry is processed.
+ * Exposing this list allows the attribution build to hook into the
+ * entry processing pipeline.
+ */
+export const entryPreProcessingCallbacks = [];
+/**
+ * Takes a performance entry and adds it to the list of worst interactions
+ * if its duration is long enough to make it among the worst. If the
+ * entry is part of an existing interaction, it is merged and the latency
+ * and entries list is updated as needed.
+ */
+export const processInteractionEntry = (entry) => {
+    entryPreProcessingCallbacks.forEach((cb) => cb(entry));
+    // Skip further processing for entries that cannot be INP candidates.
+    if (!(entry.interactionId || entry.entryType === 'first-input'))
+        return;
+    // The least-long of the 10 longest interactions.
+    const minLongestInteraction = longestInteractionList[longestInteractionList.length - 1];
+    const existingInteraction = longestInteractionMap.get(entry.interactionId);
+    // Only process the entry if it's possibly one of the ten longest,
+    // or if it's part of an existing interaction.
+    if (existingInteraction ||
+        longestInteractionList.length < MAX_INTERACTIONS_TO_CONSIDER ||
+        entry.duration > minLongestInteraction.latency) {
+        // If the interaction already exists, update it. Otherwise create one.
+        if (existingInteraction) {
+            // If the new entry has a longer duration, replace the old entries,
+            // otherwise add to the array.
+            if (entry.duration > existingInteraction.latency) {
+                existingInteraction.entries = [entry];
+                existingInteraction.latency = entry.duration;
+            }
+            else if (entry.duration === existingInteraction.latency &&
+                entry.startTime === existingInteraction.entries[0].startTime) {
+                existingInteraction.entries.push(entry);
+            }
+        }
+        else {
+            const interaction = {
+                id: entry.interactionId,
+                latency: entry.duration,
+                entries: [entry],
+            };
+            longestInteractionMap.set(interaction.id, interaction);
+            longestInteractionList.push(interaction);
+        }
+        // Sort the entries by latency (descending) and keep only the top ten.
+        longestInteractionList.sort((a, b) => b.latency - a.latency);
+        if (longestInteractionList.length > MAX_INTERACTIONS_TO_CONSIDER) {
+            longestInteractionList
+                .splice(MAX_INTERACTIONS_TO_CONSIDER)
+                .forEach((i) => longestInteractionMap.delete(i.id));
+        }
+    }
+};