diff --git a/src/split_json.cpp b/src/split_json.cpp
index 7104748..42cf97c 100644
--- a/src/split_json.cpp
+++ b/src/split_json.cpp
@@ -3,15 +3,32 @@
 #include <vector>
 #include <string>
 
-extern "C" SEXP splitString(SEXP strSEXP) {
+extern "C" SEXP split_json(SEXP strSEXP) {
     const char* str = CHAR(STRING_ELT(strSEXP, 0));
-    std::vector<std::string> result;
+    std::vector<std::string> keys;
+    std::vector<std::string> values;
+    std::vector<bool> keysNA;
+    std::vector<bool> valuesNA;
     std::string token;
     bool inQuotes = false;
     int backslashCount = 0;
+    bool isKey = true;
 
-    for (int i = 0; str[i] != '\0'; ++i) {
+    int start = 0;
+    int end = strlen(str) - 1;
+
+    // Ignore leading and trailing whitespaces
+    while (str[start] == ' ') start++;
+    while (str[end] == ' ') end--;
+
+    // Check for '{' and '}' and adjust the boundaries
+    if (str[start] == '{') start++;
+    if (str[end] == '}') end--;
+
+    for (int i = start; i <= end; ++i) {
         char ch = str[i];
+        if (ch == ' ' && !inQuotes) continue; // Skip spaces outside quotes
+
         if (ch == '\\' && !inQuotes) {
             backslashCount++;
             token += ch;
@@ -20,7 +37,19 @@ extern "C" SEXP splitString(SEXP strSEXP) {
             token += ch;
             backslashCount = 0;
         } else if ((ch == ',' || ch == ':') && !inQuotes) {
-            result.push_back(token);
+            bool isNA = token == "null";
+            if (token.front() == '"' && token.back() == '"' && token.size() > 1) {
+                token = token.substr(1, token.size() - 2); // Remove quotes
+            }
+            if (isKey) {
+                keys.push_back(token);
+                keysNA.push_back(isNA);
+                isKey = false; // Next token will be a value
+            } else {
+                values.push_back(token);
+                valuesNA.push_back(isNA);
+                isKey = true; // Next token will be a key
+            }
             token.clear();
             backslashCount = 0;
         } else {
@@ -29,15 +58,32 @@ extern "C" SEXP splitString(SEXP strSEXP) {
         }
     }
 
-    if (!token.empty()) {
-        result.push_back(token);
+    // Check the last token
+    if (!token.empty() && token != "null") {
+        if (token.front() == '"' && token.back() == '"' && token.size() > 1) {
+            token = token.substr(1, token.size() - 2); // Remove quotes
+        }
+        values.push_back(token);
+        valuesNA.push_back(token == "null");
+    } else {
+        values.push_back("");
+        valuesNA.push_back(true);
     }
 
-    SEXP ans = PROTECT(allocVector(STRSXP, result.size()));
-    for (size_t j = 0; j < result.size(); ++j) {
-        SET_STRING_ELT(ans, j, mkChar(result[j].c_str()));
+    SEXP ans = PROTECT(allocVector(VECSXP, 2)); // List with two elements
+    SEXP keysR = PROTECT(allocVector(STRSXP, keys.size()));
+    SEXP valuesR = PROTECT(allocVector(STRSXP, values.size()));
+
+    for (size_t j = 0; j < keys.size(); ++j) {
+        SET_STRING_ELT(keysR, j, keysNA[j] ? NA_STRING : mkChar(keys[j].c_str()));
     }
+    for (size_t j = 0; j < values.size(); ++j) {
+        SET_STRING_ELT(valuesR, j, valuesNA[j] ? NA_STRING : mkChar(values[j].c_str()));
+    }
+
+    SET_VECTOR_ELT(ans, 0, keysR);
+    SET_VECTOR_ELT(ans, 1, valuesR);
 
-    UNPROTECT(1);
+    UNPROTECT(3);
     return ans;
 }