feat: add DetaQuery class to create query in search

lib/src/deta_query.dart

@@ -0,0 +1,83 @@
+part of 'deta.dart';
+
+/// {@template deta_query}
+/// Create a query for search elements in the databese.
+/// {@endtemplate}
+class DetaQuery {
+  ///{@macro deta_query}
+  DetaQuery(this.key) : query = <String, dynamic>{};
+
+  DetaQuery._withPreviousQuery(this.key, this.query);
+
+  /// Key for indicate the search value.
+  final String key;
+
+  /// Query status.
+  final Map<String, dynamic> query;
+
+  /// Join the old query with a new one.
+  DetaQuery and(String key) {
+    return DetaQuery._withPreviousQuery(key, query);
+  }
+
+  /// Check the content of [key] is equal to [value].
+  DetaQuery equalTo(Object value) {
+    return _createQuery(value, '');
+  }
+
+  /// Check the content of [key] is not equal to [value].
+  DetaQuery notEqualTo(Object value) {
+    return _createQuery(value, '?ne');
+  }
+
+  /// Check the content of [key] is less than [value].
+  DetaQuery lessThan(num value) {
+    return _createQuery(value, '?lt');
+  }
+
+  /// Check the content of [key] is greater than [value].
+  DetaQuery greaterThan(num value) {
+    return _createQuery(value, '?gt');
+  }
+
+  /// Check the content of [key] isgreater than or equal to [value].
+  DetaQuery greaterThanOrEqualTo(num value) {
+    return _createQuery(value, '?gte');
+  }
+
+  /// Check the content of [key] is less than or equal to [value].
+  DetaQuery lessThanOrEqualTo(num value) {
+    return _createQuery(value, '?lte');
+  }
+
+  /// Check the content of [key] is a prefix equal to [value].
+  DetaQuery prefix(String value) {
+    return _createQuery(value, '?pfx');
+  }
+
+  /// Check the content of [key] in the range [start] and [end].
+  DetaQuery range(num start, num end) {
+    return _createQuery([start, end], '?r');
+  }
+
+  /// Check the content of [key] constains [value].
+  ///
+  /// NOTE: Only works for a list of strings, not apply to list
+  /// of other data types.
+  DetaQuery contains(String value) {
+    return _createQuery(value, '?contains');
+  }
+
+  /// Check the content of [key] does not constain [value].
+  ///
+  /// NOTE: Only works for a list of strings, not apply to list
+  /// of other data types.
+  DetaQuery notContains(String value) {
+    return _createQuery(value, '?not_contains');
+  }
+
+  DetaQuery _createQuery(Object value, String operator) {
+    query['$key$operator'] = value;
+    return DetaQuery._withPreviousQuery(key, query);
+  }
+}

test/src/deta_query_test.dart

@@ -0,0 +1,92 @@
+import 'package:deta/deta.dart';
+import 'package:test/test.dart';
+
+void main() {
+  late DetaQuery query;
+  const key = 'name';
+
+  setUp(() {
+    query = DetaQuery(key);
+  });
+
+  group('DetaQuery', () {
+    test('equalTo', () {
+      expect(
+        query.equalTo('Jhon').query,
+        equals(<String, dynamic>{key: 'Jhon'}),
+      );
+    });
+
+    test('notEqualTo', () {
+      expect(
+        query.notEqualTo('Jhon').query,
+        equals(<String, dynamic>{'$key?ne': 'Jhon'}),
+      );
+    });
+
+    test('lessThan', () {
+      expect(
+        query.lessThan(16).query,
+        equals(<String, dynamic>{'$key?lt': 16}),
+      );
+    });
+
+    test('greaterThan', () {
+      expect(
+        query.greaterThan(18).query,
+        equals(<String, dynamic>{'$key?gt': 18}),
+      );
+    });
+    test('lessThanOrEqualTo', () {
+      expect(
+        query.lessThanOrEqualTo(22).query,
+        equals(<String, dynamic>{'$key?lte': 22}),
+      );
+    });
+    test('greaterThanOrEqualTo', () {
+      expect(
+        query.greaterThanOrEqualTo(28).query,
+        equals(<String, dynamic>{'$key?gte': 28}),
+      );
+    });
+    test('prefix', () {
+      expect(
+        query.prefix('coin').query,
+        equals(<String, dynamic>{'$key?pfx': 'coin'}),
+      );
+    });
+
+    test('range', () {
+      expect(
+        query.range(16, 28).query,
+        equals(<String, dynamic>{
+          '$key?r': [16, 28]
+        }),
+      );
+    });
+    test('contains', () {
+      expect(
+        query.contains('@deta.sh').query,
+        equals(<String, dynamic>{'$key?contains': '@deta.sh'}),
+      );
+    });
+
+    test('notContains', () {
+      expect(
+        query.notContains('@deta.sh').query,
+        equals(<String, dynamic>{'$key?not_contains': '@deta.sh'}),
+      );
+    });
+
+    test('and', () {
+      expect(
+        DetaQuery('email')
+            .contains('@deta.sh')
+            .and('name')
+            .equalTo('Jhon')
+            .query,
+        equals(<String, dynamic>{'email?contains': '@deta.sh', 'name': 'Jhon'}),
+      );
+    });
+  });
+}