-type json_key()    :: atom() | string() | binary().
-type json_value()  :: boolean() | 'null' | calendar:datetime() | atom()
                     | number() | binary() | json_object() | json_array().
-type json_object() :: #{json_key() => json_value()}.
-type json_array()  :: [json_value()].
-type json_opts()   :: #{'keys' => 'atom' | 'existing_atom' | 'list'}.

-spec lejson:decode(iodata()) -> json_object() | json_array() | {error, not_json}.
-spec lejson:decode(iodata(), json_opts()) ->
                    json_object() | json_array() | {error, not_json}.

-spec lejson:encode(json_value()) -> binary().

1> l(lejson).
ok
2> M = lejson:decode(<<"{\"boolean\": [true, false],
                         \"neg_num\": -12,
                         \"floats\": [-22.3, -22.3e-12, 22.3E-12,
                                      22.3E+4, 22.3E+4, 22.3E4],
                         \"null\": null,
                         \"pos_int\": 6789,
                         \"string_value\": \"value\",
                         \"utf_value\": \"\\uC3B8 and \\uc2a9\",
                         \"arabic\": \"\\uD8B3\\ud8b5\\ud8b8\",
                         \"more unicode\": \" \\uD834 \\uDD1E \",
                         \"array\": [{\"object_inside_array\": 1}],
                         \"nested_array\": [[[79]]],
                         \"another_array\": [1,2,3,[1,[2],3],12]}">>).
#{<<"another_array">> => [1,2,3,[1,[2],3],12],
  <<"arabic">> => <<216,179,216,181,216,184>>,
  <<"array">> => [#{<<"object_inside_array">> => 1}],
  <<"boolean">> => [true,false],
  <<"floats">> => [-22.3,-2.23e-11,2.23e-11,2.23e5,2.23e5,2.23e5],
  <<"more unicode">> => <<32,216,52,32,221,30,32>>,
  <<"neg_num">> => -12,
  <<"nested_array">> => [["O"]],
  <<"null">> => null,
  <<"pos_int">> => 6789,
  <<"string_value">> => <<"value">>,
  <<"utf_value">> => <<"ø and ©"/utf8>>}
3> lejson:encode(M)
<<"{\"another_array\": [1, 2, 3, [1, [2], 3], 12],\"arabic\": \""...>>