feat: add VidIQ badge reader with unset selector

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

src/lib/vidiq.js

@@ -0,0 +1,14 @@
+// CSS selector of VidIQ's outlier badge on a video card. It stays null until the real
+// markup is captured (Task 15); until then readVidiqScore returns null for every card.
+export const VIDIQ_BADGE_SELECTOR = null;
+
+export function parseVidiqScore(text) {
+  const match = /(\d+(?:[.,]\d+)?)/.exec(text ?? '');
+  return match ? Number(match[1].replace(',', '.')) : null;
+}
+
+export function readVidiqScore(card, selector = VIDIQ_BADGE_SELECTOR) {
+  if (!selector || !card) return null;
+  const badge = card.querySelector(selector);
+  return badge ? parseVidiqScore(badge.textContent) : null;
+}

test/vidiq.test.js

@@ -0,0 +1,32 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { VIDIQ_BADGE_SELECTOR, parseVidiqScore, readVidiqScore } from '../src/lib/vidiq.js';
+
+test('parseVidiqScore extracts the first number', () => {
+  assert.equal(parseVidiqScore('12.5x'), 12.5);
+  assert.equal(parseVidiqScore('5,2x'), 5.2);
+  assert.equal(parseVidiqScore('Outlier 8'), 8);
+});
+
+test('parseVidiqScore returns null when there is no number', () => {
+  assert.equal(parseVidiqScore('no digits here'), null);
+  assert.equal(parseVidiqScore(''), null);
+  assert.equal(parseVidiqScore(null), null);
+  assert.equal(parseVidiqScore(undefined), null);
+});
+
+test('readVidiqScore returns null while no selector is configured', () => {
+  assert.equal(VIDIQ_BADGE_SELECTOR, null);
+  const card = { querySelector: () => ({ textContent: '9x' }) };
+  assert.equal(readVidiqScore(card), null);
+});
+
+test('readVidiqScore reads the badge inside a card', () => {
+  const card = { querySelector: (selector) => (selector === '.badge' ? { textContent: '7.5x' } : null) };
+  assert.equal(readVidiqScore(card, '.badge'), 7.5);
+});
+
+test('readVidiqScore returns null when the card has no badge or no card is given', () => {
+  assert.equal(readVidiqScore({ querySelector: () => null }, '.badge'), null);
+  assert.equal(readVidiqScore(null, '.badge'), null);
+});