A compact JSON beautifier

json-pretty

// Highly compact JSON beautifier/formatter. Not very efficient and could definitely be improved. The main issue is with 
// the number of allocations and memory presure being placed on the heap and garbage collector if the input is large.
// It is the shortest in terms of code size though.
// Source: http://stackoverflow.com/questions/4580397/json-formatter-in-c/24782322#24782322

private const string INDENT_STRING = "    ";

static string FormatJson(string json) {

    int indentation = 0;
    int quoteCount = 0;
    var result = 
        from ch in json
        let quotes = ch == '"' ? quoteCount++ : quoteCount
        let lineBreak = ch == ',' && quotes % 2 == 0 ? ch + Environment.NewLine +  String.Concat(Enumerable.Repeat(INDENT_STRING, indentation)) : null
        let openChar = ch == '{' || ch == '[' ? ch + Environment.NewLine + String.Concat(Enumerable.Repeat(INDENT_STRING, ++indentation)) : ch.ToString()
        let closeChar = ch == '}' || ch == ']' ? Environment.NewLine + String.Concat(Enumerable.Repeat(INDENT_STRING, --indentation)) + ch : ch.ToString()
        select lineBreak == null    
                    ? openChar.Length > 1 
                        ? openChar 
                        : closeChar
                    : lineBreak;

    return String.Concat(result);
}