Implement fromJson factory in data classes.

moor/example/example.g.dart

@@ -18,6 +18,12 @@ class Category {
       description: stringType.mapFromDatabaseResponse(data['description']),
     );
   }
+  factory Category.fromJson(Map<String, dynamic> json) {
+    return Category(
+      id: json['id'] as int,
+      description: json['description'] as String,
+    );
+  }
   Map<String, dynamic> toJson() {
     return {
       'id': id,
@@ -106,6 +112,14 @@ class Recipe {
       category: intType.mapFromDatabaseResponse(data['category']),
     );
   }
+  factory Recipe.fromJson(Map<String, dynamic> json) {
+    return Recipe(
+      id: json['id'] as int,
+      title: json['title'] as String,
+      instructions: json['instructions'] as String,
+      category: json['category'] as int,
+    );
+  }
   Map<String, dynamic> toJson() {
     return {
       'id': id,
@@ -223,6 +237,13 @@ class Ingredient {
       caloriesPer100g: intType.mapFromDatabaseResponse(data['calories']),
     );
   }
+  factory Ingredient.fromJson(Map<String, dynamic> json) {
+    return Ingredient(
+      id: json['id'] as int,
+      name: json['name'] as String,
+      caloriesPer100g: json['caloriesPer100g'] as int,
+    );
+  }
   Map<String, dynamic> toJson() {
     return {
       'id': id,
@@ -327,6 +348,13 @@ class IngredientInRecipe {
       amountInGrams: intType.mapFromDatabaseResponse(data['amount']),
     );
   }
+  factory IngredientInRecipe.fromJson(Map<String, dynamic> json) {
+    return IngredientInRecipe(
+      recipe: json['recipe'] as int,
+      ingredient: json['ingredient'] as int,
+      amountInGrams: json['amountInGrams'] as int,
+    );
+  }
   Map<String, dynamic> toJson() {
     return {
       'recipe': recipe,

moor/test/data/tables/todos.g.dart

@@ -26,6 +26,15 @@ class TodoEntry {
       category: intType.mapFromDatabaseResponse(data['category']),
     );
   }
+  factory TodoEntry.fromJson(Map<String, dynamic> json) {
+    return TodoEntry(
+      id: json['id'] as int,
+      title: json['title'] as String,
+      content: json['content'] as String,
+      targetDate: json['targetDate'] as DateTime,
+      category: json['category'] as int,
+    );
+  }
   Map<String, dynamic> toJson() {
     return {
       'id': id,
@@ -164,6 +173,12 @@ class Category {
       description: stringType.mapFromDatabaseResponse(data['`desc`']),
     );
   }
+  factory Category.fromJson(Map<String, dynamic> json) {
+    return Category(
+      id: json['id'] as int,
+      description: json['description'] as String,
+    );
+  }
   Map<String, dynamic> toJson() {
     return {
       'id': id,
@@ -255,6 +270,14 @@ class User {
           uint8ListType.mapFromDatabaseResponse(data['profile_picture']),
     );
   }
+  factory User.fromJson(Map<String, dynamic> json) {
+    return User(
+      id: json['id'] as int,
+      name: json['name'] as String,
+      isAwesome: json['isAwesome'] as bool,
+      profilePicture: json['profilePicture'] as Uint8List,
+    );
+  }
   Map<String, dynamic> toJson() {
     return {
       'id': id,
@@ -370,6 +393,12 @@ class SharedTodo {
       user: intType.mapFromDatabaseResponse(data['user']),
     );
   }
+  factory SharedTodo.fromJson(Map<String, dynamic> json) {
+    return SharedTodo(
+      todo: json['todo'] as int,
+      user: json['user'] as int,
+    );
+  }
   Map<String, dynamic> toJson() {
     return {
       'todo': todo,

moor_generator/lib/src/writer/data_class_writer.dart

@@ -26,7 +26,8 @@ class DataClassWriter {
     // Also write parsing factory
     _writeMappingConstructor(buffer);
 
-    // And a serializer method
+    // And a serializer and deserializer method
+    _writeFromJson(buffer);
     _writeToJson(buffer);
 
     // And a convenience method to copy data from this class.
@@ -97,12 +98,29 @@ class DataClassWriter {
     buffer.write(');}\n');
   }
 
+  void _writeFromJson(StringBuffer buffer) {
+    final dataClassName = table.dartTypeName;
+
+    buffer
+      ..write('factory $dataClassName.fromJson(Map<String, dynamic> json) {\n')
+      ..write('return $dataClassName(');
+
+    for (var column in table.columns) {
+      final getter = column.dartGetterName;
+      final type = column.dartTypeName;
+
+      buffer.write("$getter: json['$getter'] as $type,");
+    }
+
+    buffer.write(');}\n');
+  }
+
   void _writeToJson(StringBuffer buffer) {
     buffer.write('Map<String, dynamic> toJson() {\n return {');
 
     for (var column in table.columns) {
       final getter = column.dartGetterName;
-      buffer.write('\'$getter\': $getter,');
+      buffer.write("'$getter': $getter,");
     }
 
     buffer.write('};}');