Implement the localizer helper API

module/utils/localizer.mjs

@@ -0,0 +1,32 @@
+const config = Object.preventExtensions({
+	subKeyPattern: /@(?<key>[a-zA-Z.]+)/gm,
+	maxDepth: 10,
+});
+
+export function localizer(key, args = {}, depth = 0) {
+	/** @type {string} */
+	let localized = game.i18n.format(key, args);
+	const subkeys = localized.matchAll(config.subKeyPattern);
+
+	// Short-cut to help prevent infinite recursion
+	if (depth > config.maxDepth) {
+		return localized;
+	};
+
+	/*
+	Helps prevent recursion on the same key so that we aren't doing excess work.
+	*/
+	const localizedSubkeys = new Map();
+	for (const match of subkeys) {
+		const subkey = match.groups.key;
+		if (localizedSubkeys.has(subkey)) { continue };
+		localizedSubkeys.set(subkey, localizer(subkey, args, depth + 1));
+	};
+
+	return localized.replace(
+		config.subKeyPattern,
+		(_fullMatch, subkey) => {
+			return localizedSubkeys.get(subkey);
+		},
+	);
+};