keyof and typeof

const palette = {
	primary: '#222222',
	accent: '#ff6600',
}

type PaletteKey = keyof typeof palette

const sizes = ['sm', 'md', 'lg'] as const
type Size = (typeof sizes)[number]

1. Create UserKey as the union of User's keys
2. Create getUserProperty(user, key) that returns the value at that key, with key constrained to UserKey
3. Create Config from the existing config value, and ConfigKey from Config's keys
4. Preserve literal types on httpMethods, then create HttpMethod from that array
5. Create makeRequest(method, url) that returns a string like "GET /api/users"
6. Export getUserProperty, makeRequest, config, and httpMethods

• getUserProperty({ id: '1', name: 'Alice', email: 'a@b.com', age: 30 }, 'name') → 'Alice'
• makeRequest('GET', '/api/users') → 'GET /api/users'
• config.apiUrl stays 'https://api.example.com' and config.timeout stays 5000