Add Handlebars helpers

module/utils/Localizer.mjs

@@ -0,0 +1,37 @@
+import { localizerConfig } from "../config.mjs";
+
+export function handlebarsLocalizer(key, ...args) {
+	let data = args[0];
+	if (args.length === 1) { data = args[0].hash };
+	if (key instanceof Handlebars.SafeString) { key = key.toString() };
+	const localized = localizer(key, data);
+	return localized;
+};
+
+export function localizer(key, args = {}, depth = 0) {
+	/** @type {string} */
+	let localized = game.i18n.format(key, args);
+	const subkeys = localized.matchAll(localizerConfig.subKeyPattern);
+
+	// Short-cut to help prevent infinite recursion
+	if (depth > localizerConfig.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(
+		localizerConfig.subKeyPattern,
+		(_fullMatch, subkey) => {
+			return localizedSubkeys.get(subkey);
+		},
+	);
+};