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. Use keyof to get the keys of an object type
2. Use typeof to extract types from values
3. Combine typeof with as const for literal types
4. Create type-safe accessor functions