Function itemsToRegexp

lib/util/compileBooleanMatcher.js:217–317

(itemsArr)

 * @returns {string} regexp
 */
const itemsToRegexp = (itemsArr) => {
	if (itemsArr.length === 1) {
		return quoteMeta(itemsArr[0]);
	}
	/** @type {string[]} */
	const finishedItems = [];

	// merge single char items: (a|b|c|d|ef) => ([abcd]|ef)
	let countOfSingleCharItems = 0;
	for (const item of itemsArr) {
		if (item.length === 1) {
			countOfSingleCharItems++;
		}
	}
	// special case for only single char items
	if (countOfSingleCharItems === itemsArr.length) {
		return `[${charsToCharClassContent(itemsArr)}]`;
	}
	/** @type {Set<string>} */
	const items = new Set(itemsArr.sort());
	if (countOfSingleCharItems > 2) {
		/** @type {string[]} */
		const singleCharItems = [];
		for (const item of items) {
			if (item.length === 1) {
				singleCharItems.push(item);
				items.delete(item);
			}
		}
		finishedItems.push(`[${charsToCharClassContent(singleCharItems)}]`);
	}

	// special case for 2 items with common prefix/suffix
	if (finishedItems.length === 0 && items.size === 2) {
		const prefix = getCommonPrefix(itemsArr);
		const suffix = getCommonSuffix(
			itemsArr.map((item) => item.slice(prefix.length))
		);
		if (prefix.length > 0 || suffix.length > 0) {
			return `${quoteMeta(prefix)}${itemsToRegexp(
				itemsArr.map((i) => i.slice(prefix.length, -suffix.length || undefined))
			)}${quoteMeta(suffix)}`;
		}
	}

	// special case for 2 items with common suffix
	if (finishedItems.length === 0 && items.size === 2) {
		/** @type {SetIterator<string>} */
		const it = items[Symbol.iterator]();
		const a = /** @type {string} */ (it.next().value);
		const b = /** @type {string} */ (it.next().value);
		if (a.length > 0 && b.length > 0 && a.slice(-1) === b.slice(-1)) {
			return `${itemsToRegexp([a.slice(0, -1), b.slice(0, -1)])}${quoteMeta(
				a.slice(-1)
			)}`;
		}
	}