Added unidentified actors and actor count filters.

utils/parse-range.js

@@ -0,0 +1,40 @@
+const numberPattern = /^\d+$/;
+const letterPattern = /^[a-z]$/i;
+
+// ranges: 3 is exactly 3, 2- is at least 2, -4 is at most 4, 2-4 is between 2 and 4 inclusive
+// comma is accepted as a legacy separator for closed ranges, e.g. age=22,30 from older links
+// values not matching the pattern invalidate the range, which keeps them safe to use in queries
+export function parseRange(rangeString, { pattern = numberPattern, parse = Number } = {}) {
+	const parts = String(rangeString ?? '').trim().split(/[-,]/);
+
+	if (parts.length > 2 || parts.every((part) => part === '') || parts.some((part) => part !== '' && !pattern.test(part))) {
+		return null;
+	}
+
+	const [minString, maxString = minString] = parts; // no separator means an exact value
+
+	return {
+		min: minString ? parse(minString) : null,
+		max: maxString ? parse(maxString) : null,
+	};
+}
+
+// single letter cup sizes, matching the cup filter's regex character class
+export function parseLetterRange(rangeString) {
+	return parseRange(rangeString, {
+		pattern: letterPattern,
+		parse: (letter) => letter.toUpperCase(),
+	});
+}
+
+export function formatRange(range) {
+	if (!range || (range.min === null && range.max === null)) {
+		return undefined;
+	}
+
+	if (range.min === range.max) {
+		return String(range.min);
+	}
+
+	return `${range.min ?? ''}-${range.max ?? ''}`;
+}