readJson method
Reads a json file from the assets folder.
Implementation
Future<Map<String, dynamic>> readJson(
String fileName, {
String? package,
}) async {
final cacheKey = package == null ? fileName : 'packages/$package/$fileName';
if (!_files.containsKey(cacheKey)) {
_files[cacheKey] = await _readJson(fileName, package: package);
}
assert(
_files[cacheKey] is _JsonAsset,
'"$cacheKey" was previously loaded as a different type',
);
return (_files[cacheKey]! as _JsonAsset).value;
}