A simple helper to map states of a snapshot coming from a StreamBuilder

snapshot_helper.dart

import 'package:flutter/material.dart';

typedef SnapshotBuilder<T> = Widget Function(AsyncSnapshot<T>);

class SnapshotHelper<T> {
  final AsyncSnapshot<T> snapshot;

  SnapshotHelper._(this.snapshot);

  factory SnapshotHelper.of(AsyncSnapshot snapshot) =>
      SnapshotHelper._(snapshot);
  Widget getWidget(
      {SnapshotBuilder<T> onData,
      SnapshotBuilder<T> onError,
      SnapshotBuilder<T> onLoading}) {
    if (snapshot.hasError) {
      return onError(snapshot);
    } else if (snapshot.connectionState == ConnectionState.waiting) {
      return onLoading(snapshot);
    } else if (snapshot.connectionState == ConnectionState.active &&
        !snapshot.hasData) {
      return onLoading(snapshot);
    } else if (snapshot.hasData && !snapshot.hasError) {
      return onData(snapshot);
    }
    return null;
  }
}