Testing jsonEncode with a class that has a toJson method.

json_encode.dart

import 'dart:convert';

void main() {
  final foo = Foo('bar');
  print(foo);
  print(foo.foo);
  print(jsonEncode(foo));
  print(jsonEncode([foo, foo, foo]));
}

class Foo {
  Foo(this.foo);

  final String foo;

  Map<String, dynamic> toJson() {
    return {'foo': foo};
  }
}