output_options.md

Output Options

daw::json::to_json allows optional policy flags to control the output. The defaults are specified below under Format Policy Flags. All the enum's below are in the daw::json::options namespace

Example

The example below shows output with the defaults and with Pretty formatting enabled. To see a working example using this code, refer to cookbook_output_flags1_test.cpp

struct OutputFlags1 {
  std::string s;
  std::vector<int> ary;
};

namespace daw::json {
  template<>
  struct json_data_contract<OutputFlags1> {
    static constexpr char const s[] = "s";
    static constexpr char const ary[] = "ary";
    using type = json_member_list<json_string<s>, json_array<ary, int>>;

    static inline auto to_json_data( OutputFlags1 const &v ) {
      return std::forward_as_tuple( v.s, v.ary );
    }
  };
} // namespace daw::json

int main( ) {
  using namespace daw::json::options;
  auto const v = OutputFlags1{ "Hello", { 1, 2, 3 } };
  puts( daw::json::to_json( v ).c_str( ) );
  puts( daw::json::to_json( v, output_flags<SerializationFormat::Pretty> ).c_str( ) );
}

The program will output

{"s":"Hello","ary":[1,2,3]}
{
  "s": "Hello",
  "ary": [
    1,
    2,
    3
  ]
}

Format Policy Flags

SerializationFormat

Enable or disable formatted output

Values

• Minified - Output the minimal JSON document
• Pretty - Use newlines and indentation to format JSON document

Default

• Minified

IndentationType

Control how the file is indented

Values

• Tab - use tab character for indentation
• Space1 - Indent 1 space
• Space2 - Indent 2 spaces
• Space3 - Indent 3 spaces
• Space4 - Indent 4 spaces
• Space5 - Indent 5 spaces
• Space8 - Indent 8 spaces
• Space10 - Indent 10 spaces :) https://youtu.be/SsoOG6ZeyUI

Default

• Space2

RestrictedStringOutput

Allow for a JSON document that is ASCII only and each byte has a value <= 0x7F

Values

• None - Do not restrict to 7bit ASCII
• OnlyAllow7bitStrings - Restrict all string member values and all member names to 7bits, escaping all values >= 0x7F.
• ErrorInvalidUTF8 - Throw an error when invalid UTF8 is encountered

Default

• ErrorInvalidUTF8

NewLineDelimiter

Change how newlines are delimited

Values

• n - Use \n to delimit newlines
• rn - Use \r\n to delimit newlines

Default

• n

OutputTrailingComma

With arrays/classes output optionally output a trailing comma

Values

• No - Do not output trailing comma's. This is conformant
• Yes - Add non-conformant trailing commas to array elements and class members

Default

• No