read method

Future<FileConfig> read(String languageTag, { String? fileName, TFileReaderFunction? fileReader, })

Reads a locale file and registers it with the active TranslationManager. Returns the loaded FileConfig.

fileReader (parameter) overrides the instance-level fileReader for this single call. If both are null, this throws StateError — the previous assert-based check was a debug-mode-only guard and would have produced a confusing NPE in release builds.

Implementation

Future<FileConfig> read(
  String languageTag, {
  String? fileName,
  TFileReaderFunction? fileReader,
}) async {
  final effectiveReader = fileReader ?? this.fileReader;
  if (effectiveReader == null) {
    throw StateError(
      'TranslationFileReader.read: no fileReader provided. Pass one to '
      'the constructor or to read() directly.',
    );
  }
  if (languageTag.isEmpty && (fileName == null || fileName.isEmpty)) {
    throw ArgumentError.value(
      languageTag,
      'languageTag',
      'languageTag must be non-empty when fileName is not provided.',
    );
  }
  // Use posix joining unconditionally. Flutter's `rootBundle` only
  // accepts forward-slash paths, and `dart:io` accepts both, so
  // posix is the only style that works everywhere without per-host
  // normalisation.
  final filePath = posix.joinAll([
    ...translationsDirPath,
    fileName ?? '$languageTag.${fileType.extension}',
  ]);
  final fileConfig = FileConfig(
    ref: ConfigFileRef(
      ref: languageTag,
      type: fileType,
      read: () => effectiveReader(filePath),
    ),
    settings: const PatternSettings(),
    mapper: mapper,
  );
  return TranslationManager.setConfig(fileConfig);
}