diff --git a/DESCRIPTION b/DESCRIPTION
index 7c44b1a..cfbf20b 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: jsonify
 Type: Package
 Title: Convert Between 'R' Objects and Javascript Object Notation (JSON)
-Version: 1.0.0001
+Version: 1.0.0002
 Date: 2019-11-03
 Authors@R: c(
     person("David", "Cooley", ,"dcooley@symbolix.com.au", role = c("aut", "cre")),
diff --git a/R/scratch.R b/R/scratch.R
index dd410eb..c8a645c 100644
--- a/R/scratch.R
+++ b/R/scratch.R
@@ -37,6 +37,7 @@
 # )
 # 
 # cat( jsonify:::rcpp_to_ndjson(lst, FALSE, -1L, TRUE, TRUE, "row") )
+# cat( jsonify:::rcpp_to_ndjson(lst, FALSE, -1L, TRUE, TRUE, "column") )
 # 
 # N <- 1e6
 # data <- data.frame(
diff --git a/R/to_json.R b/R/to_json.R
index 004b467..5ab3f24 100644
--- a/R/to_json.R
+++ b/R/to_json.R
@@ -56,6 +56,47 @@ to_json <- function( x, unbox = FALSE, digits = NULL, numeric_dates = TRUE,
 #' 
 #' Converts R objects to ndjson
 #' 
+#' @inheritParams to_json
+#' 
+#' @details 
+#' 
+#' Lists are converted to ndjson non-recursively. That is, each of the objects
+#' in the list at the top level are converted to a new-line JSON object. Any nested
+#' sub-elements are then contained within that JSON object. See examples
+#' 
+#' @examples 
+#' 
+#' to_ndjson( 1:5 )
+#' to_ndjson( letters )
+#' 
+#' mat <- matrix(1:6, ncol = 2)
+#' 
+#' to_ndjson( x = mat )
+#' to_ndjson( x = mat, by = "col" )
+#' 
+#' df <- data.frame(
+#'   x = 1:5
+#'   , y = letters[1:5]
+#'   , z = as.Date(seq(18262, 18262 + 4, by = 1 ), origin = "1970-01-01" )
+#'   )
+#' 
+#' to_ndjson( x = df )
+#' to_ndjson( x = df, numeric_dates = FALSE )
+#' to_ndjson( x = df, factors_as_string = FALSE )
+#' to_ndjson( x = df, by = "column" )
+#' 
+#' ## Lists are non-recurisve; only elements `x` and `y` are converted to ndjson
+#' lst <- list(
+#'   x = 1:5
+#'   , y = list(
+#'     a = letters[1:5]
+#'     , b = data.frame(i = 10:15, j = 20:25)
+#'   )
+#' )
+#'  
+#' to_ndjson( x = lst )
+#' to_ndjson( x = lst, by = "column")
+#' 
 #' 
 #' @export
 to_ndjson <- function( x, unbox = FALSE, digits = NULL, numeric_dates = TRUE, 
@@ -67,7 +108,7 @@ to_ndjson <- function( x, unbox = FALSE, digits = NULL, numeric_dates = TRUE,
 }
 
 handle_digits <- function( digits ) {
-  if( is.null( digits ) ) return(-1)
+  if( is.null( digits ) ) return(-1L)
   return( as.integer( digits ) )
 }
 
diff --git a/inst/include/jsonify/to_json/api.hpp b/inst/include/jsonify/to_json/api.hpp
index 57d5012..f9db291 100644
--- a/inst/include/jsonify/to_json/api.hpp
+++ b/inst/include/jsonify/to_json/api.hpp
@@ -33,8 +33,9 @@ namespace api {
   //   // loop over rows or columns, 
   // }
   
-  inline Rcpp::StringVector to_ndjson(
+  inline void to_ndjson(
       Rcpp::DataFrame& df,
+      std::ostringstream& os,
       bool unbox = false,
       int digits = -1,
       bool numeric_dates = true,
@@ -48,7 +49,7 @@ namespace api {
     Rcpp::StringVector column_names = df.names();
     bool in_data_frame = true;
     
-    std::ostringstream os; // for storing the final string of ndjson
+    //std::ostringstream os; // for storing the final string of ndjson
     
     if( by == "row" ) {
       
@@ -107,12 +108,13 @@ namespace api {
       
     }
     
-    Rcpp::StringVector sv = os.str();
-    return sv;
+    // Rcpp::StringVector sv = os.str();
+    // return sv;
   }
 
-  inline Rcpp::StringVector to_ndjson(
+  inline void to_ndjson(
       Rcpp::LogicalMatrix mat,
+      std::ostringstream& os,
       bool unbox = false,
       std::string by = "row"
   ) {
@@ -121,7 +123,7 @@ namespace api {
     R_xlen_t n_col = mat.ncol();
     R_xlen_t i;
     
-    std::ostringstream os; // for storing the final string of ndjson
+    //std::ostringstream os; // for storing the final string of ndjson
     
     if( by == "row" ) {
       
@@ -154,12 +156,13 @@ namespace api {
     } else {
       Rcpp::stop("jsonify - expecting matrix operatinos by row or column");
     }
-    Rcpp::StringVector sv = os.str();
-    return sv;
+    // Rcpp::StringVector sv = os.str();
+    // return sv;
   }
 
-  inline Rcpp::StringVector to_ndjson(
+  inline void to_ndjson(
       Rcpp::IntegerMatrix mat,
+      std::ostringstream& os,
       bool unbox = false,
       std::string by = "row"
   ) {
@@ -168,7 +171,7 @@ namespace api {
     R_xlen_t n_col = mat.ncol();
     R_xlen_t i;
     
-    std::ostringstream os; // for storing the final string of ndjson
+    //std::ostringstream os; // for storing the final string of ndjson
     
     if( by == "row" ) {
       
@@ -201,13 +204,14 @@ namespace api {
     } else {
       Rcpp::stop("jsonify - expecting matrix operatinos by row or column");
     }
-    Rcpp::StringVector sv = os.str();
-    return sv;
+    // Rcpp::StringVector sv = os.str();
+    // return sv;
   }
   
   
-  inline Rcpp::StringVector to_ndjson(
+  inline void to_ndjson(
     Rcpp::NumericMatrix mat,
+    std::ostringstream& os,
     bool unbox = false,
     int digits = -1,
     std::string by = "row"
@@ -217,7 +221,7 @@ namespace api {
     R_xlen_t n_col = mat.ncol();
     R_xlen_t i;
     
-    std::ostringstream os; // for storing the final string of ndjson
+    //std::ostringstream os; // for storing the final string of ndjson
     
     if( by == "row" ) {
       
@@ -250,12 +254,13 @@ namespace api {
     } else {
       Rcpp::stop("jsonify - expecting matrix operatinos by row or column");
     }
-    Rcpp::StringVector sv = os.str();
-    return sv;
+    // Rcpp::StringVector sv = os.str();
+    // return sv;
   }
 
   inline Rcpp::StringVector to_ndjson(
       Rcpp::StringMatrix mat,
+      std::ostringstream& os,
       bool unbox = false,
       std::string by = "row"
   ) {
@@ -264,7 +269,7 @@ namespace api {
     R_xlen_t n_col = mat.ncol();
     R_xlen_t i;
     
-    std::ostringstream os; // for storing the final string of ndjson
+    //std::ostringstream os; // for storing the final string of ndjson
     
     if( by == "row" ) {
       
@@ -295,12 +300,54 @@ namespace api {
       }
       
     } else {
-      Rcpp::stop("jsonify - expecting matrix operatinos by row or column");
+      Rcpp::stop("jsonify - expecting matrix operations by row or column");
+    }
+    // Rcpp::StringVector sv = os.str();
+    // return sv;
+  }
+
+  inline void to_ndjson(
+      Rcpp::List& lst,
+      std::ostringstream& os,
+      bool unbox = false,
+      int digits = -1,
+      bool numeric_dates = true,
+      bool factors_as_string = true,
+      std::string by = "row"
+  ) {
+    R_xlen_t n = lst.size();
+    R_xlen_t i;
+    
+    for( i = 0; i < n; ++i ) {
+      rapidjson::StringBuffer sb;
+      rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
+      SEXP s = lst[ i ];
+      jsonify::writers::complex::write_value( writer, s, unbox, digits, numeric_dates, factors_as_string, by );
+      os << sb.GetString();
+      os << '\n';
     }
-    Rcpp::StringVector sv = os.str();
-    return sv;
+    
+  }
+
+  template < int RTYPE >
+  inline void to_ndjson(
+      Rcpp::Vector< RTYPE > obj,
+      std::ostringstream& os,
+      bool unbox = false,
+      int digits = -1,
+      bool numeric_dates = true,
+      bool factors_as_string = true
+      ) {
+    
+    rapidjson::StringBuffer sb;
+    rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
+    jsonify::writers::simple::write_value( writer, obj, unbox, digits, numeric_dates, factors_as_string );
+    os << sb.GetString();
+    os << '\n';
+    
   }
 
+  // lists are non-recursive; only the first element is ndjsonified...
   inline Rcpp::StringVector to_ndjson(
     SEXP obj,
     bool unbox = false,
@@ -310,111 +357,69 @@ namespace api {
     std::string by = "row"
   ) {
 
-    // rapidjson::StringBuffer sb;
-    // rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
-    // 
-    // std::ostringstream os; // for storing the final string of ndjson
+    std::ostringstream os; // for storing the final string of ndjson
     
-    // TODO
-    // the way ndjson is created depends on the type of input object
-    // a list will be element-wise
-    // data.frame / matrix will be whatever 'by' is set
-    // other cases not handled?
-    //
-    // given the rapidjson DOM doesn't accept '\n' characters,
-    // I may have to iterate over the object and create one json object at a time
-    // and output to an OSStream, append '\n', 
-    // then at the end convert to StringVector.
     switch( TYPEOF( obj ) ) {
     case LGLSXP: {
       if( !Rf_isMatrix( obj ) ) {
-        Rcpp::LogicalVector lv = Rcpp::as< Rcpp::LogicalVector >( obj );
-        std::ostringstream os; // for storing the final string of ndjson
-        
-        rapidjson::StringBuffer sb;
-        rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
-        jsonify::writers::simple::write_value( writer, lv, unbox );
-        
-        os << sb.GetString();
-        os << '\n';
-        Rcpp::StringVector res = os.str();
-        return res;
+
+        to_ndjson< LGLSXP >( obj, os, unbox, digits, numeric_dates, factors_as_string );
+          
       } else {
         Rcpp::LogicalMatrix lm = Rcpp::as< Rcpp::LogicalMatrix >( obj );
-        return to_ndjson( lm, unbox, by );
+        to_ndjson( lm, os, unbox, by );
       }
+      break;
     }
     case INTSXP: {
       if( !Rf_isMatrix( obj ) ) {
-        Rcpp::IntegerVector iv = Rcpp::as< Rcpp::IntegerVector >( obj );
-        std::ostringstream os; // for storing the final string of ndjson
-        
-        rapidjson::StringBuffer sb;
-        rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
-        jsonify::writers::simple::write_value( writer, iv, unbox );
+      
+        to_ndjson< INTSXP >( obj, os, unbox, digits, numeric_dates, factors_as_string );
         
-        os << sb.GetString();
-        os << '\n';
-        Rcpp::StringVector res = os.str();
-        return res;
       } else {
         Rcpp::IntegerMatrix im = Rcpp::as< Rcpp::IntegerMatrix >( obj );
-        return to_ndjson( im, unbox, by );
+        to_ndjson( im, os, unbox, by );
+
       }
+      break;
     }
     case REALSXP: {
       if( !Rf_isMatrix( obj ) ) {
-        Rcpp::NumericVector nv = Rcpp::as< Rcpp::NumericVector >( obj );
       
-        std::ostringstream os; // for storing the final string of ndjson
-        
-        rapidjson::StringBuffer sb;
-        rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
-        jsonify::writers::simple::write_value( writer, nv, unbox, digits );
+        to_ndjson< REALSXP >( obj, os, unbox, digits, numeric_dates, factors_as_string );
         
-        os << sb.GetString();
-        os << '\n';
-        Rcpp::StringVector res = os.str();
-        return res;
       } else {
         Rcpp::NumericMatrix nm = Rcpp::as< Rcpp::NumericMatrix >( obj );
-        return to_ndjson( nm, unbox, digits, by );
+        to_ndjson( nm, os, unbox, digits, by );
+        
       }
+      break;
     }
     case STRSXP: {
       if( !Rf_isMatrix( obj ) ) {
-        Rcpp::StringVector sv = Rcpp::as< Rcpp::StringVector >( obj );
-      
-        std::ostringstream os; // for storing the final string of ndjson
-        
-        rapidjson::StringBuffer sb;
-        rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
-        jsonify::writers::simple::write_value( writer, sv, unbox );
         
-        os << sb.GetString();
-        os << '\n';
-        Rcpp::StringVector res = os.str();
-        return res;
+        to_ndjson< STRSXP >( obj, os, unbox, digits, numeric_dates, factors_as_string );
         
       } else {
         Rcpp::StringMatrix sm = Rcpp::as< Rcpp::StringMatrix >( obj );
-        return to_ndjson( sm, unbox, by );
+        to_ndjson( sm, os, unbox, by );
+        
       }
+      break;
     }
     case VECSXP: {
       if( Rf_inherits( obj, "data.frame") ) {
+      
         Rcpp::DataFrame df = Rcpp::as< Rcpp::DataFrame >( obj );
-        return to_ndjson( df, unbox, digits, numeric_dates, factors_as_string, by );
+        to_ndjson( df, os, unbox, digits, numeric_dates, factors_as_string, by );
+      
       } else {
         // list
         Rcpp::List lst = Rcpp::as< Rcpp::List >( obj );
-        R_xlen_t n = lst.size();
-        R_xlen_t i;
-        for( i = 0; i < n; ++i ) {
-          SEXP s = lst[ i ];
-          return to_ndjson( s, unbox, digits, numeric_dates, factors_as_string, by );
-        }
+        to_ndjson( lst, os, unbox, digits, numeric_dates, factors_as_string, by );
+
       }
+      break;
     }
     default: {
       Rcpp::stop("jsonify - expecting a matrix, data.frame or list");
@@ -422,12 +427,9 @@ namespace api {
 
     }
     
-    return Rcpp::StringVector::create();
-
-    //rapidjson::StringBuffer sb;
-    //rapidjson::Writer < rapidjson::StringBuffer > writer( sb );
-    //jsonify::writers::complex::write_value( writer, lst, unbox, digits, numeric_dates, factors_as_string, by );
-    //return jsonify::utils::finalise_json( sb );
+    Rcpp::StringVector js = os.str();
+    js.attr("class") = "json";
+    return js;
   }
 
 
diff --git a/inst/include/jsonify/to_json/writers/ndjson.hpp b/inst/include/jsonify/to_json/writers/ndjson.hpp
new file mode 100644
index 0000000..e69de29
diff --git a/inst/include/jsonify/to_json/writers/simple.hpp b/inst/include/jsonify/to_json/writers/simple.hpp
index 7a924ef..120529f 100644
--- a/inst/include/jsonify/to_json/writers/simple.hpp
+++ b/inst/include/jsonify/to_json/writers/simple.hpp
@@ -342,14 +342,14 @@ namespace simple {
       write_value( writer, lv, unbox );
       break;
     }
-    case STRSXP: {
+    default: {
       Rcpp::StringVector sv = Rcpp::as< Rcpp::StringVector >( sexp );
       write_value( writer, sv, unbox );
       break;
     }
-    default: {
-      Rcpp::stop("Unknown R object type");
-    }
+    // default: {
+    //   Rcpp::stop("Unknown R object type");
+    // }
     }
   }
   
@@ -491,7 +491,7 @@ namespace simple {
       bool unbox = false
     ) {
     
-    Rcpp::LogicalVector this_row = mat(row, Rcpp::_);
+    Rcpp::LogicalVector this_row = mat( row, Rcpp::_ );
     write_value( writer, this_row, unbox );
   }
   
diff --git a/man/to_ndjson.Rd b/man/to_ndjson.Rd
index ce238c4..f41e84b 100644
--- a/man/to_ndjson.Rd
+++ b/man/to_ndjson.Rd
@@ -7,6 +7,63 @@
 to_ndjson(x, unbox = FALSE, digits = NULL, numeric_dates = TRUE,
   factors_as_string = TRUE, by = "row")
 }
+\arguments{
+\item{x}{object to convert to JSON}
+
+\item{unbox}{logical indicating if single-value arrays should be 'unboxed', 
+that is, not contained inside an array.}
+
+\item{digits}{integer specifying the number of decimal places to round numerics.
+Default is \code{NULL} - no rounding}
+
+\item{numeric_dates}{logical indicating if dates should be treated as numerics. 
+Defaults to TRUE for speed. If FALSE, the dates will be coerced to character in UTC time zone}
+
+\item{factors_as_string}{logical indicating if factors should be treated as strings. Defaults to TRUE.}
+
+\item{by}{either "row" or "column" indicating if data.frames and matrices should be processed
+row-wise or column-wise. Defaults to "row"}
+}
 \description{
 Converts R objects to ndjson
 }
+\details{
+Lists are converted to ndjson non-recursively. That is, each of the objects
+in the list at the top level are converted to a new-line JSON object. Any nested
+sub-elements are then contained within that JSON object. See examples
+}
+\examples{
+
+to_ndjson( 1:5 )
+to_ndjson( letters )
+
+mat <- matrix(1:6, ncol = 2)
+
+to_ndjson( x = mat )
+to_ndjson( x = mat, by = "col" )
+
+df <- data.frame(
+  x = 1:5
+  , y = letters[1:5]
+  , z = as.Date(seq(18262, 18262 + 4, by = 1 ), origin = "1970-01-01" )
+  )
+
+to_ndjson( x = df )
+to_ndjson( x = df, numeric_dates = FALSE )
+to_ndjson( x = df, factors_as_string = FALSE )
+to_ndjson( x = df, by = "column" )
+
+## Lists are non-recurisve; only elements `x` and `y` are converted to ndjson
+lst <- list(
+  x = 1:5
+  , y = list(
+    a = letters[1:5]
+    , b = data.frame(i = 10:15, j = 20:25)
+  )
+)
+ 
+to_ndjson( x = lst )
+to_ndjson( x = lst, by = "column")
+
+
+}
diff --git a/tests/testthat/test-to_ndjson.R b/tests/testthat/test-to_ndjson.R
new file mode 100644
index 0000000..b9e503f
--- /dev/null
+++ b/tests/testthat/test-to_ndjson.R
@@ -0,0 +1,38 @@
+context("to_ndjson")
+
+test_that("objects converted to ndjson",{
+
+  ## vectors - as per json
+  expect_equal( unclass( to_ndjson( 1:5 ) ),"[1,2,3,4,5]\n")
+  expect_equal( unclass( to_ndjson( letters[1:5] ) ), '["a","b","c","d","e"]\n')
+
+  mat <- matrix(1:6, ncol = 2)
+
+  expect_equal( unclass( to_ndjson( x = mat ) ), '[1,4]\n[2,5]\n[3,6]\n')
+  expect_equal( unclass( to_ndjson( x = mat, by = "col" ) ), '[1,2,3]\n[4,5,6]\n' )
+
+  df <- data.frame(
+    x = 1:5
+    , y = letters[1:5]
+    , z = as.Date(seq(18262, 18262 + 4, by = 1 ), origin = "1970-01-01" )
+    )
+
+  expect_equal( unclass( to_ndjson( x = df ) ) , "{\"x\":1,\"y\":\"a\",\"z\":18262.0}\n{\"x\":2,\"y\":\"b\",\"z\":18263.0}\n{\"x\":3,\"y\":\"c\",\"z\":18264.0}\n{\"x\":4,\"y\":\"d\",\"z\":18265.0}\n{\"x\":5,\"y\":\"e\",\"z\":18266.0}\n" )
+  expect_equal( unclass( to_ndjson( x = df, numeric_dates = FALSE ) ), "{\"x\":1,\"y\":\"a\",\"z\":\"2020-01-01\"}\n{\"x\":2,\"y\":\"b\",\"z\":\"2020-01-02\"}\n{\"x\":3,\"y\":\"c\",\"z\":\"2020-01-03\"}\n{\"x\":4,\"y\":\"d\",\"z\":\"2020-01-04\"}\n{\"x\":5,\"y\":\"e\",\"z\":\"2020-01-05\"}\n" )
+  expect_equal( unclass( to_ndjson( x = df, factors_as_string = FALSE ) ), "{\"x\":1,\"y\":1,\"z\":18262.0}\n{\"x\":2,\"y\":2,\"z\":18263.0}\n{\"x\":3,\"y\":3,\"z\":18264.0}\n{\"x\":4,\"y\":4,\"z\":18265.0}\n{\"x\":5,\"y\":5,\"z\":18266.0}\n" )
+  expect_equal( unclass( to_ndjson( x = df, by = "column" ) ), "{\"x\":[1,2,3,4,5]}\n{\"y\":[\"a\",\"b\",\"c\",\"d\",\"e\"]}\n{\"z\":[18262.0,18263.0,18264.0,18265.0,18266.0]}\n" )
+
+  ## Lists are non-recurisve; only elements `x` and `y` are converted to ndjson
+  lst <- list(
+    x = 1:5
+    , y = list(
+      a = letters[1:5]
+      , b = data.frame(i = 10:15, j = 20:25)
+    )
+  )
+
+  expect_equal( unclass( to_ndjson( x = lst ) ), "[1,2,3,4,5]\n{\"a\":[\"a\",\"b\",\"c\",\"d\",\"e\"],\"b\":[{\"i\":10,\"j\":20},{\"i\":11,\"j\":21},{\"i\":12,\"j\":22},{\"i\":13,\"j\":23},{\"i\":14,\"j\":24},{\"i\":15,\"j\":25}]}\n" )
+  expect_equal( unclass( to_ndjson( x = lst, by = "column") ), "[1,2,3,4,5]\n{\"a\":[\"a\",\"b\",\"c\",\"d\",\"e\"],\"b\":{\"i\":[10,11,12,13,14,15],\"j\":[20,21,22,23,24,25]}}\n" )
+
+
+})
\ No newline at end of file