diff --git a/threads.js b/threads.js
index 4147ac19..7405bd5b 100644
--- a/threads.js
+++ b/threads.js
@@ -2467,16 +2467,16 @@ Process.prototype.reportLetter = function (idx, string) {
         return '';
     }
     var i = +(idx || 0),
-        str = (string || '').toString();
+        str = isNil(string) ? '' : string.toString();
     return str[i - 1] || '';
 };
 
-Process.prototype.reportStringSize = function (string) {
-    if (string instanceof List) { // catch a common user error
-        return string.length();
+Process.prototype.reportStringSize = function (data) {
+    if (data instanceof List) { // catch a common user error
+        return data.length();
     }
-    var str = (string || '').toString();
-    return str.length;
+
+    return isNil(data) ? 0 : data.toString().length;
 };
 
 Process.prototype.reportUnicode = function (string) {
@@ -2501,10 +2501,10 @@ Process.prototype.reportTextSplit = function (string, delimiter) {
     if (!contains(types, delType)) {
         throw new Error('expecting a text delimiter instead of a ' + delType);
     }
-    str = (string || '').toString();
+    str = isNil(string) ? '' string.toString();
     switch (this.inputOption(delimiter)) {
     case 'line':
-        // Unicode Compliant Line Splitting (Platform independent)
+        // Unicode compliant line splitting (platform independent)
         // http://www.unicode.org/reports/tr18/#Line_Boundaries
         del = /\r\n|[\n\v\f\r\x85\u2028\u2029]/;
         break;
@@ -2522,7 +2522,7 @@ Process.prototype.reportTextSplit = function (string, delimiter) {
         del = '';
         break;
     default:
-        del = (delimiter || '').toString();
+        del = isNil(delimiter) ? '' : delimiter.toString();
     }
     return new List(str.split(del));
 };