chore: extract capPageViews helper and remove dead writeNamespacedFieldWithinBudget

src/pageViewStorage.ts

@@ -17,6 +17,10 @@ export interface PageEvent {
   activeTimeOnPage?: number;
 }
 
+function capPageViews(views: PageEvent[]): PageEvent[] {
+  return views.slice(-PAGE_VIEWS_MAX_COUNT);
+}
+
 export function migrateLegacyPageViewStorage(loggingService: LoggingService | null): void {
   const legacyViews = readJSON(LEGACY_PAGE_VIEWS_KEY);
   if (legacyViews === null) {
@@ -50,15 +54,15 @@ export function loadPageViews(loggingService: LoggingService | null): PageEvent[
 }
 
 export function writePageViews(pageViews: PageEvent[]): boolean {
-  return writeNamespacedField(LS_NAMESPACE_KEY, LS_PAGE_VIEWS_FIELD, pageViews.slice(-PAGE_VIEWS_MAX_COUNT));
+  return writeNamespacedField(LS_NAMESPACE_KEY, LS_PAGE_VIEWS_FIELD, capPageViews(pageViews));
 }
 
 export function clearPageViews(): void {
   removeNamespacedField(LS_NAMESPACE_KEY, LS_PAGE_VIEWS_FIELD);
 }
 
 export function buildPageEvents(pageViews: PageEvent[]): PageEvent[] {
-  const views = pageViews.slice(-PAGE_VIEWS_MAX_COUNT);
+  const views = capPageViews(pageViews);
   return views.map((pageView, index) => {
     const activeTimeOnSite = pageView.activeTimeOnSite;
     const hasActiveTime = activeTimeOnSite !== undefined && Number.isFinite(activeTimeOnSite);

src/storage.ts

@@ -63,35 +63,3 @@ export function removeNamespacedField(namespaceKey: string, field: string): void
     writeJSON(namespaceKey, next);
   }
 }
-
-export function writeNamespacedFieldWithinBudget(
-  namespaceKey: string,
-  field: string,
-  records: unknown[],
-  maxLength: number,
-): boolean {
-  // Operate on a copy so the caller's array isn't trimmed as a side effect.
-  const remaining = records.slice();
-
-  const evictOldest = (): boolean => {
-    if (remaining.length <= 1) {
-      return false;
-    }
-    remaining.shift();
-    return true;
-  };
-
-  // Two limits: our own soft cap (maxLength), then the browser's hard quota,
-  // which is shared across the origin and only surfaces when setItem throws.
-  let overBudget = JSON.stringify(remaining).length > maxLength;
-  while (overBudget && evictOldest()) {
-    overBudget = JSON.stringify(remaining).length > maxLength;
-  }
-
-  let written = writeNamespacedField(namespaceKey, field, remaining);
-  while (!written && evictOldest()) {
-    written = writeNamespacedField(namespaceKey, field, remaining);
-  }
-
-  return written;
-}

test/src/pageViewStorage.spec.ts

@@ -154,8 +154,6 @@ describe('pageViewStorage', () => {
       }));
       const result = buildPageEvents(views);
       expect(result).toHaveLength(25);
-      // First record in the capped window should have activeTimeOnPage derived from
-      // the next record within the slice, not from the unsliced original array.
       expect(result[0].activeTimeOnPage).toBe(1000);
       expect(result[24].activeTimeOnPage).toBeUndefined();
     });

test/src/storage.spec.ts

@@ -7,7 +7,6 @@ import {
   readNamespacedField,
   writeNamespacedField,
   removeNamespacedField,
-  writeNamespacedFieldWithinBudget,
 } from '../../src/storage';
 
 describe('storage: key-agnostic localStorage helpers', () => {
@@ -156,68 +155,6 @@ describe('storage: key-agnostic localStorage helpers', () => {
       expect(readJSON(NAMESPACE_KEY)).toEqual({ other: 1 });
     });
   });
-
-  describe('writeNamespacedFieldWithinBudget', () => {
-    const NAMESPACE_KEY = 'mp-rokt-kit';
-    const BUDGET = 1024;
-
-    it('writes all records unchanged when under budget', () => {
-      const records = [{ id: 1 }, { id: 2 }];
-      expect(writeNamespacedFieldWithinBudget(NAMESPACE_KEY, 'pageViews', records, BUDGET)).toBe(true);
-      expect(records).toHaveLength(2);
-      expect(readNamespacedField(NAMESPACE_KEY, 'pageViews')).toEqual([{ id: 1 }, { id: 2 }]);
-    });
-
-    it('evicts oldest-first until the serialized size is within budget', () => {
-      const big = 'x'.repeat(300);
-      const records = [
-        { id: 'a', v: big },
-        { id: 'b', v: big },
-        { id: 'c', v: big },
-        { id: 'd', v: big },
-      ];
-      expect(writeNamespacedFieldWithinBudget(NAMESPACE_KEY, 'pageViews', records, BUDGET)).toBe(true);
-
-      const stored = readNamespacedField(NAMESPACE_KEY, 'pageViews') as { id: string }[];
-      expect(JSON.stringify(stored).length).toBeLessThanOrEqual(BUDGET);
-      expect(stored[stored.length - 1].id).toBe('d');
-      expect(stored.map((r) => r.id)).not.toContain('a');
-    });
-
-    it('keeps at least the newest record even when it alone exceeds the budget', () => {
-      const records = [{ id: 'newest', v: 'x'.repeat(BUDGET * 2) }];
-      expect(writeNamespacedFieldWithinBudget(NAMESPACE_KEY, 'pageViews', records, BUDGET)).toBe(true);
-      expect(readNamespacedField(NAMESPACE_KEY, 'pageViews')).toEqual([{ id: 'newest', v: 'x'.repeat(BUDGET * 2) }]);
-    });
-
-    it('evicts and retries when writes fail, then persists', () => {
-      let calls = 0;
-      const realSetItem = Storage.prototype.setItem;
-      vi.spyOn(Storage.prototype, 'setItem').mockImplementation(function (this: Storage, key: string, value: string) {
-        calls += 1;
-        if (calls <= 2) {
-          throw new DOMException('quota', 'QuotaExceededError');
-        }
-        return realSetItem.call(this, key, value);
-      });
-
-      const records = [{ id: 'a' }, { id: 'b' }, { id: 'c' }, { id: 'd' }];
-      expect(writeNamespacedFieldWithinBudget(NAMESPACE_KEY, 'pageViews', records, BUDGET)).toBe(true);
-
-      const stored = readNamespacedField(NAMESPACE_KEY, 'pageViews') as { id: string }[];
-      // 2 failed writes evict the oldest twice (a, then b), leaving [c, d].
-      expect(stored.map((r) => r.id)).toEqual(['c', 'd']);
-    });
-
-    it('returns false when even a single record cannot be written', () => {
-      vi.spyOn(Storage.prototype, 'setItem').mockImplementation(() => {
-        throw new DOMException('quota', 'QuotaExceededError');
-      });
-      const records = [{ id: 'a' }, { id: 'b' }];
-      expect(writeNamespacedFieldWithinBudget(NAMESPACE_KEY, 'pageViews', records, BUDGET)).toBe(false);
-      expect(records).toEqual([{ id: 'a' }, { id: 'b' }]);
-    });
-  });
 });
 
 describe('isLocalStorageAvailable', () => {