Flutter config from simple json asset with no depth, just a draft and totally unoptimized

config.dart

import 'dart:convert';
import 'package:flutter/material.dart';

class Config extends InheritedWidget {
  final Map<String, dynamic> config;

  final Widget child;

  Config({Key? key, required this.child, required this.config})
      : super(key: key, child: child);

  static Config of(BuildContext context) {
    Config? c = context.dependOnInheritedWidgetOfExactType<Config>();

    if (c == null) {
      throw new AssertionError('Config was not set');
    }

    return c;
  }

  @override
  bool updateShouldNotify(Config oldWidget) {
    return false;
  }

  /// Usage:
  ///
  /// ```dart
  /// return Config.fromAsset(
  ///    context: context,
  ///    path: "assets/config.json",
  ///    loading: SplashScreen(),
  ///    onError: (error) => Text('${error}'),
  ///    child: ChangeNotifierProvider(
  ///      create: (ctx) => ProductsProvider(),
  ///      child: Text('mah child here'),
  ///    ),
  ///  );
  /// ```
  static Widget fromAsset({
    required BuildContext context,
    required String path,
    required Widget child,
    Widget Function(Object?)? onError,
    Widget? loading,
  }) {
    return FutureBuilder(
        future: DefaultAssetBundle.of(context)
            .loadString(path)
            .then((config) => jsonDecode(config)),
        builder: (context, snapshot) {
          if (snapshot.hasData) {
            return Config(
              config: snapshot.data as Map<String, dynamic>,
              child: child,
            );
          } else if (snapshot.hasError) {
            if (onError != null) {
              return onError(snapshot.error);
            } else {
              throw new AssertionError(snapshot.error);
            }
          } else {
            if (loading != null) {
              return loading;
            }

            return Container();
          }
        });
  }

  /// Usage:
  ///
  /// const stringValue = Config.of(context).get<String>(key);
  /// const intValue = Config.of(context).get<int>(key);
  T get<T>(String key) {
    if (!this.config.containsKey(key)) {
      throw new AssertionError('Unknown config key: ${key}');
    }
    if (this.config[key] is T) {
      return this.config[key] as T;
    }

    throw new AssertionError('Type mismatch for ${key}');
  }
}