Beyond Primitives, Lists, and Maps

jsonx is an extended JSON library that supports the encoding and decoding of arbitrary objects. jsonx can decode a JSON string into a strongly typed object which gets type checking and code autocompletion support, or encode an arbitrary object into a JSON string.

Decode a JSON String

decode(String text, {reviver(key, value), Type type});

Decodes the JSON string text given the optional type type.

The optional reviver function is called once for each object or list property that has been parsed during decoding. The key argument is either the integer list index for a list property, the map string for object properties, or null for the final result.

The default reviver (when not provided) is the identity function.

The optional type parameter specifies the type to which text should be decoded. Since Dart doesn't allow passing a generic type as an argument, one must create an instance of that generic type and pass the instance's runtimeType as the value of type.

If type is omitted, this method is equivalent to JSON.decode in dart:convert library.


class Person {
  String name;
  int age;

Person p = decode('{ "name": "Tom", "age": 20 }', type: Person);
print(; // Tom

List<int> list = decode('[1,2,3]', type: <int>[].runtimeType);
print(list[1]); // 2

Encode an Object

String encode(object)

Encodes object as a JSON string.

The encoding happens as below:

  1. Tries to encode object directly
  2. If (1) fails, tries to call object.toJson() to convert object into an encodable value

  3. If (2) fails, tries to use mirrors to convert object into en encodable value


class Person {
  Person(, this.age);
  String name;
  int age;

var p = new Person('Jerry', 20);
print(encode(p)); // {"name":"Jerry","age":20}



An extended JSON library that supports the encoding and decoding of arbitrary objects.