/**
 * Creates a random URL-safe string for IDs and unique fallback values.
 *
 * @param len Length of the string to generate.
 */
export default function randomId(len: number = 21): string {
	const charset = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-';
	let result = '';
	for (let i = 0; i < len; i += 1) {
		const randomIndex = Math.floor(Math.random() * charset.length);
		result += charset[randomIndex];
	}
	return result;
}
/**
 * Create random string (`randomId`), function for creating a unique suffix on each call.
 *
 * Useful for knowing a string will always have a unique suffix but can still be targeted easily with RegEx.
 *
 * ---
 * `const [randomId, withUniqueSuffix] = idWithUniqueSuffix();`
 */
export function idWithUniqueSuffix(): [string, () => string] {
	const randomStr = randomId();
	let callCount = 0;
	return [randomStr, () => `${randomStr}-${++callCount}`];
}