Field validators

@Min and @Max constrain a numeric field to a range. They are the annotations cloud_firestore_odm had, with the same meaning.

import 'package:firestore_odm/firestore_odm.dart';

@firestoreOdm
class Movie {
  const Movie({required this.id, required this.likes, required this.rating});

  @DocumentIdField()
  final String id;

  @Min(0)
  final int likes;

  @Min(0)
  @Max(100)
  final double rating;
}

Put them on the field of a plain class, or on the constructor parameter of a freezed class:

@freezed
@firestoreOdm
abstract class Rating with _$Rating {
  const factory Rating({
    @DocumentIdField() required String id,
    @Min(0) @Max(10) required int points,
  }) = _Rating;

  factory Rating.fromJson(Map<String, dynamic> json) => _$RatingFromJson(json);
}

When they are checked

Before anything is written. The generated converters check every bound and throw a FirestoreODMValidationException, so Firestore never sees the value:

try {
  await odm.movies.set(Movie(id: 'm1', likes: -1, rating: 50));
} on FirestoreODMValidationException catch (e) {
  print(e.message); // likes must be at least 0, got -1
  print(e.field);   // likes
  print(e.code);    // out_of_range
}

All three write paths are covered:

write	checked
set(model), create(model)	every bounded field, including nested models
patch(($) => [$.likes.set(-1)])	the value being set, at any nesting depth
patch(($) => [$.likes.increment(1)])	no — increment is a relative change the server applies; nothing is written that needs checking

A null value (an unset optional field) and a non-numeric value pass, as in cloud_firestore_odm.

Rules

• @Min/@Max apply to int, double and num fields. On any other type the build fails with a clear error instead of generating code that cannot work.
• Both annotations can be combined, and each can be used alone.
• The bound is checked in the generated converter, so it covers every write path in your code, and values already in Firestore are not re-validated when they are read.
• @Min/@Max are the range checks; anything else (a non-empty string, a pattern) belongs in the model's constructor or in the code that builds it.