feat: add JSON and CSV export

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/lib/export.js

@@ -0,0 +1,34 @@
+export const COLUMNS = [
+  'videoId',
+  'title',
+  'url',
+  'thumbnailUrl',
+  'channelId',
+  'channelTitle',
+  'channelUrl',
+  'subscribers',
+  'views',
+  'publishedAt',
+  'durationSec',
+  'isShort',
+  'score',
+  'vidiqScore',
+  'foundOn',
+  'firstSeenAt',
+  'updatedAt',
+];
+
+export function toJson(records) {
+  return JSON.stringify(records, null, 2);
+}
+
+function csvCell(value) {
+  if (value === null || value === undefined) return '';
+  const text = String(value);
+  return /[",\r\n]/.test(text) ? `"${text.replaceAll('"', '""')}"` : text;
+}
+
+export function toCsv(records) {
+  const lines = [COLUMNS.join(','), ...records.map((r) => COLUMNS.map((c) => csvCell(r[c])).join(','))];
+  return lines.join('\r\n') + '\r\n';
+}

test/export.test.js

@@ -0,0 +1,61 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { COLUMNS, toCsv, toJson } from '../src/lib/export.js';
+
+const record = (over = {}) => ({
+  videoId: 'dQw4w9WgXcQ',
+  title: 'Hello',
+  url: 'https://www.youtube.com/watch?v=dQw4w9WgXcQ',
+  thumbnailUrl: 'https://i.ytimg.com/vi/dQw4w9WgXcQ/hqdefault.jpg',
+  channelId: 'UC1',
+  channelTitle: 'Chan',
+  channelUrl: 'https://www.youtube.com/@chan',
+  subscribers: 1000,
+  views: 50000,
+  publishedAt: '2026-10-01T00:00:00Z',
+  durationSec: 600,
+  isShort: false,
+  score: 50,
+  vidiqScore: null,
+  foundOn: 'home',
+  firstSeenAt: '2026-10-25T10:00:00.000Z',
+  updatedAt: '2026-10-25T10:00:00.000Z',
+  ...over,
+});
+
+test('toCsv writes a header and one row per record', () => {
+  const csv = toCsv([record()]);
+  assert.equal(
+    csv,
+    COLUMNS.join(',') +
+      '\r\n' +
+      'dQw4w9WgXcQ,Hello,https://www.youtube.com/watch?v=dQw4w9WgXcQ,' +
+      'https://i.ytimg.com/vi/dQw4w9WgXcQ/hqdefault.jpg,UC1,Chan,https://www.youtube.com/@chan,' +
+      '1000,50000,2026-10-01T00:00:00Z,600,false,50,,home,' +
+      '2026-10-25T10:00:00.000Z,2026-10-25T10:00:00.000Z\r\n',
+  );
+});
+
+test('toCsv quotes commas, quotes and newlines', () => {
+  const csv = toCsv([record({ title: 'He said "hi", then\nleft' })]);
+  assert.ok(csv.includes('"He said ""hi"", then\nleft"'));
+});
+
+test('toCsv writes null and undefined as empty cells and keeps booleans readable', () => {
+  const csv = toCsv([record({ subscribers: null, vidiqScore: 7.5, isShort: true, channelUrl: undefined })]);
+  const row = csv.split('\r\n')[1];
+  assert.ok(row.includes(',true,'));
+  assert.ok(row.includes(',7.5,'));
+  assert.ok(row.includes('Chan,,,50000')); // channelUrl and subscribers empty
+});
+
+test('toCsv of no records is just the header', () => {
+  assert.equal(toCsv([]), COLUMNS.join(',') + '\r\n');
+});
+
+test('toJson pretty-prints and round-trips', () => {
+  const records = [record(), record({ videoId: 'abcdefghijk' })];
+  const text = toJson(records);
+  assert.ok(text.includes('\n  '));
+  assert.deepEqual(JSON.parse(text), records);
+});