const HEX = '[0-9a-fA-F]'
const UUID = `${HEX}{8}-${HEX}{4}-[1-8]${HEX}{3}-[89abAB]${HEX}{3}-${HEX}{12}`

/** Internal shared spelling rule for runtime checks and JSON-schema-compatible schemas. */
export function entityIdPattern(): RegExp {
	// JavaScript's $ also matches before a final newline. The final lookahead
	// requires the actual end so no accepted id can carry a control character.
	return new RegExp(String.raw`^${UUID}$(?![\s\S])`)
}