Adds a storage manager

src/lib/utils/storage.ts

@@ -0,0 +1,43 @@
+/**
+ * A localStorage utility class that can be
+ * used to remember keyed preferences/options
+ */
+
+const KEY_PREFIX = "__documentcloud_";
+
+export interface StorageManager {
+  key: (subkey: string) => string;
+}
+
+export class StorageManager {
+  constructor(key: string) {
+    this.key = (subkey) => `${KEY_PREFIX}${key}_${subkey}`;
+  }
+
+  get<R, T>(key: string, defaultValue?: T): R | T | null {
+    try {
+      const value = JSON.parse(localStorage.getItem(this.key(key)));
+      if (value === null) return defaultValue ?? null;
+      return value;
+    } catch (e) {
+      // Local storage not available
+      return defaultValue ?? null;
+    }
+  }
+
+  set<V>(key: string, value: V) {
+    try {
+      localStorage.setItem(this.key(key), JSON.stringify(value));
+    } catch (e) {
+      // Local storage not available
+    }
+  }
+
+  remove(key: string) {
+    try {
+      localStorage.removeItem(this.key(key))
+    } catch (e) {
+      // Local storage not available
+    }
+  }
+}

src/lib/utils/tests/storage.test.ts

@@ -0,0 +1,13 @@
+import { test, expect } from 'vitest';
+import { StorageManager } from "../storage";
+
+test("StorageManager", () => {
+  const s = new StorageManager('settings');
+  expect(s.key('property')).toEqual('__documentcloud_settings_property');
+  s.set('property', 12345);
+  expect(s.get('property')).toEqual(12345);
+  expect(s.get('unsetProp', 67890)).toEqual(67890);
+  expect(s.get('unsetProp')).toBeNull();
+  s.remove('property');
+  expect(s.get('property')).toBeNull();
+});