getCookie

1/**
2 * Retrieves the value of a cookie by name.
3 *
4 * @param name - The name of the cookie to retrieve.
5 * @returns The decoded value of the cookie, or undefined if not found.
6 */
7export function getCookie(name: string): string | undefined {
8  const encodedName = encodeURIComponent(name) + '=';
9  const cookies = document.cookie.split('; ');
10  for (const cookie of cookies) {
11    if (cookie.startsWith(encodedName)) {
12      return decodeURIComponent(cookie.slice(encodedName.length));
13    }
14  }
15  return undefined;
16}

1beforeEach(() => {
2  Object.defineProperty(document, 'cookie', {
3    writable: true,
4    configurable: true,
5    value: ''
6  });
7});
8
9test('returns undefined for nonexistent cookie', () => {
10  document.cookie = 'user=john';
11  expect(getCookie('missing')).toBeUndefined();
12});
13
14test('retrieves value of existing cookie', () => {
15  document.cookie = 'session=abc123';
16  expect(getCookie('session')).toBe('abc123');
17});
18
19test('returns decoded value', () => {
20  const encoded = encodeURIComponent('va=lue!');
21  document.cookie = `key=${encoded}`;
22  expect(getCookie('key')).toBe('va=lue!');
23});
24
25test('handles multiple cookies', () => {
26  document.cookie = 'a=1; b=2; c=3';
27  expect(getCookie('b')).toBe('2');
28});
29
30test('works with encoded cookie name', () => {
31  const name = 'user name';
32  const value = 'value';
33  document.cookie = `${encodeURIComponent(name)}=${value}`;
34  expect(getCookie(name)).toBe(value);
35});