first commit

src/common/utils/cursor.util.spec.ts

@@ -0,0 +1,13 @@
+import { decodeOffsetCursor, encodeOffsetCursor } from './cursor.util';
+
+describe('cursor util', () => {
+  it('encodes and decodes cursor offsets', () => {
+    const cursor = encodeOffsetCursor(40);
+    expect(decodeOffsetCursor(cursor)).toBe(40);
+  });
+
+  it('returns null on invalid cursor', () => {
+    expect(decodeOffsetCursor('%%%invalid%%%')).toBeNull();
+    expect(decodeOffsetCursor(encodeOffsetCursor(-1))).toBeNull();
+  });
+});

src/common/utils/cursor.util.ts

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+export const encodeOffsetCursor = (offset: number): string =>
+  Buffer.from(String(offset), 'utf8').toString('base64url');
+
+export const decodeOffsetCursor = (cursor?: string): number | null => {
+  if (!cursor) {
+    return null;
+  }
+
+  try {
+    const raw = Buffer.from(cursor, 'base64url').toString('utf8');
+    const parsed = Number(raw);
+    if (!Number.isInteger(parsed) || parsed < 0) {
+      return null;
+    }
+    return parsed;
+  } catch {
+    return null;
+  }
+};

src/common/utils/hash.util.ts

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+import * as bcrypt from 'bcrypt';
+
+export const hashValue = async (value: string, saltRounds: number): Promise<string> =>
+  bcrypt.hash(value, saltRounds);
+
+export const compareHash = async (value: string, hashedValue: string): Promise<boolean> =>
+  bcrypt.compare(value, hashedValue);