Utility script

• All my tests pass
• Output contains “3 files renamed, 1 skipped”
• standardName("Till 7.PNG", {"prefix": "r", "date": "…) returns "r-2026-01-31-till-7.png"
• No uncaught errors

// Utility script: rename a batch of files to one standard name, as a dry run first.
// Options live at the top, inputs are checked, and the script ends with one summary line.
const OPTIONS = {
  prefix: 'receipt',
  date: '2026-03-02',
  dryRun: true,
};

/** "Till 3 Receipt (copy).PDF" → "receipt-2026-03-02-till-3.pdf"; null when the name has nothing usable. */
export function standardName(name, { prefix, date }) {
  const dot = name.lastIndexOf('.');
  const ext = dot > 0 ? name.slice(dot + 1).toLowerCase() : '';
  const stem = (dot > 0 ? name.slice(0, dot) : name)
    .toLowerCase()
    .replace(/\(copy\)|copy of|receipt/g, ' ')
    .replace(/[^a-z0-9]+/g, '-')
    .replace(/^-+|-+$/g, '');
  if (!stem || !ext) return null;
  return `${prefix}-${date}-${stem}.${ext}`;
}

/** Plans every rename; two files that would get the same name get -2, -3… instead of overwriting each other. */
export function planRenames(names, opts) {
  if (!/^\d{4}-\d{2}-\d{2}$/.test(opts.date)) throw new Error('date must look like 2026-03-02');
  const used = new Set();
  const plan = [], skipped = [];
  for (const from of names) {
    let to = standardName(from, opts);
    if (!to) { skipped.push(from); continue; }
    const first = to;
    for (let n = 2; used.has(to); n++) to = first.replace(/(\.[a-z0-9]+)$/, `-${n}$1`);
    used.add(to);
    if (to !== from) plan.push({ from, to });
  }
  return { plan, skipped };
}

const files = ['Till 3 Receipt.PDF', 'till 3 receipt (copy).pdf', 'Till-7 receipt.pdf', 'notes'];
const { plan, skipped } = planRenames(files, OPTIONS);
for (const r of plan) console.log(`${OPTIONS.dryRun ? '[dry run] ' : ''}${r.from} → ${r.to}`);
if (skipped.length) console.log('Skipped (no name or extension):', skipped.join(', '));
console.log(`${plan.length} files renamed, ${skipped.length} skipped`);

import { standardName, planRenames } from './rename';

const opts = { prefix: 'receipt', date: '2026-03-02' };

test('standardName: lower case, dashes, prefix and date first', () => {
  expect(standardName('Till 3 Receipt.PDF', opts)).toBe('receipt-2026-03-02-till-3.pdf');
});
test('standardName: a name with no extension is skipped', () => {
  expect(standardName('notes', opts)).toBe(null);
});
test('planRenames: two files never get the same name', () => {
  const { plan } = planRenames(['Till 3 Receipt.pdf', 'till 3 receipt (copy).pdf'], opts);
  expect(plan.map((r) => r.to)).toEqual(['receipt-2026-03-02-till-3.pdf', 'receipt-2026-03-02-till-3-2.pdf']);
});
test('planRenames: a bad date stops before anything is renamed', () => {
  expect(() => planRenames(['a.pdf'], { prefix: 'x', date: '2/3/26' })).toThrow('date must look like');
});