fix(i18n): handle utf-8 escape sequences in message bundle properties files (#12784)

Author: pskelin

packages/tools/lib/i18n/toJSON.js

@@ -14,8 +14,31 @@ const assets = require('../../assets-meta.js');
 
 const allLanguages = assets.languages.all;
 
+/**
+ * The translation system has a configuration whether to return UTF-8 sequences
+ * or the actual characters. This function inlines UTF-8 sequences to actual characters.
+ * 
+ * For example, it converts "Keine Produkte erf\u00FCgbar" to "Keine Produkte verfügbar"
+ * This makes the JSON files more readable and smaller.
+ */
+function inlineUTF(properties) {
+	for (const key in properties) {
+		if (Object.prototype.hasOwnProperty.call(properties, key)) {
+			try {
+				// escape double quotes to avoid JSON parse error
+				const escaped = properties[key].replaceAll("\"", "\\\"");
+				properties[key] = JSON.parse(`"${escaped}"`); // utilize JSON parser to decode UTF-8 sequences
+			} catch (e) {
+				// in case of error, just keep the original string
+				console.log(`Warning: failed to inline UTF-8 for key "${key}" with value "${properties[key]}"`);
+			}
+		}
+	}
+	return properties;
+}
+
 const convertToJSON = async (file, distPath) => {
-	const properties = PropertiesReader(file)._properties;
+	const properties = inlineUTF(PropertiesReader(file)._properties);
 	const filename = path.basename(file, path.extname(file));
 	const language = filename.match(/^messagebundle_(.*?)$/)[1];
 	if (!allLanguages.includes(language)) {