nc-photos/app/lib/stream_util.dart

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

class ValueStreamBuilder<T> extends StreamBuilder<T> {
  ValueStreamBuilder({
    super.key,
    ValueStream<T>? stream,
    required super.builder,
  }) : super(
          stream: stream,
          initialData: stream?.value,
        );
}

class ValueStreamBuilderEx<T> extends StreamBuilder<T> {
  ValueStreamBuilderEx({
    super.key,
    ValueStream<T>? stream,
    required StreamWidgetBuilder<T> builder,
  }) : super(
          stream: stream,
          initialData: stream?.value,
          builder: builder.snapshotBuilder ??
              (context, snapshot) {
                return builder.valueBuilder!(context, snapshot.requireData);
              },
        );
}

class StreamWidgetBuilder<T> {
  const StreamWidgetBuilder._({
    this.snapshotBuilder,
    this.valueBuilder,
  });

  const StreamWidgetBuilder.snapshot(AsyncWidgetBuilder<T> builder)
      : this._(snapshotBuilder: builder);
  const StreamWidgetBuilder.value(
      Widget Function(BuildContext context, T value) builder)
      : this._(valueBuilder: builder);

  final AsyncWidgetBuilder<T>? snapshotBuilder;
  final Widget Function(BuildContext context, T value)? valueBuilder;
}