in dartfn/lib/src/stagehand/common.dart [71:85]
String substituteVars(String str, Map<String, String> vars) {
if (vars.keys.any((element) => element.contains(_nonValidSubstituteRegExp))) {
throw ArgumentError('vars.keys can only contain letters.');
}
return str.replaceAllMapped(_substituteRegExp, (match) {
final item = vars[match[1]];
if (item == null) {
return match[0]!;
} else {
return item;
}
});
}