insertRegistryEntry function

String? insertRegistryEntry(String file, { required String variable, required String type, required String key, required String value, })

Adds '<key>': <value>, to the Map<String, <type>> <variable> declared in file.

Handles the release-guarded form Metro generates (kReleaseMode ? const {} : {...}) as well as a plain map literal. Returns null when key is already in file or there is no such map.

Implementation

String? insertRegistryEntry(
  String file, {
  required String variable,
  required String type,
  required String key,
  required String value,
}) {
  if (file.contains("'$key'") || file.contains('"$key"')) return null;
  final String declaration = 'final Map<String, $type> $variable = ';

  final RegExpMatch? guarded = _guardedMap(variable, type).firstMatch(file);
  if (guarded != null) {
    final String entries = _entries(
      guarded.group(1)!,
    ).map((String line) => '        $line\n').join();
    return file.replaceRange(
      guarded.start,
      guarded.end,
      '${declaration}kReleaseMode\n'
      '    ? const {}\n'
      '    : {\n'
      '$entries'
      "        '$key': $value,\n"
      '      };',
    );
  }

  final RegExpMatch? plain = _plainMap(variable, type).firstMatch(file);
  if (plain == null) return null;
  String entries = plain.group(1)!.trimRight();
  if (entries.trim().isNotEmpty && !entries.endsWith(',')) entries += ',';
  return file.replaceRange(
    plain.start,
    plain.end,
    '$declaration{'
    '$entries\n'
    "  '$key': $value,\n"
    '};',
  );
}