diff --git a/.gitignore b/.gitignore
index bc55255..159e4fc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@ node_modules
 misc/coverage.html
 ctest/sauce*
 *.sheetjs
+*.tgz
diff --git a/bits/00_header.js b/bits/00_header.js
index 2829d16..2cd78d2 100644
--- a/bits/00_header.js
+++ b/bits/00_header.js
@@ -10,7 +10,6 @@ var PRINTJ/*:PRINTJModule*/ = /*::(*/{}/*:: :any)*/;
 export const version = PRINTJ.version;
 #else
 var PRINTJ/*:PRINTJModule*/;
-#include "05_polyfill.js"
 (function (factory/*:(a:any)=>void*/)/*:void*/ {
 	/*jshint ignore:start */
 	/*eslint-disable */
diff --git a/bits/01_version.js b/bits/01_version.js
index eafee04..aafa57c 100644
--- a/bits/01_version.js
+++ b/bits/01_version.js
@@ -1 +1 @@
-PRINTJ.version = '1.2.0';
+PRINTJ.version = '1.2.1';
diff --git a/bits/05_polyfill.js b/bits/05_polyfill.js
deleted file mode 100644
index 6275ed3..0000000
--- a/bits/05_polyfill.js
+++ /dev/null
@@ -1,38 +0,0 @@
-// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat
-if (!String.prototype.repeat) {
-  String.prototype.repeat = function(count) {
-    'use strict';
-    if (this == null) {
-      throw new TypeError('can\'t convert ' + this + ' to object');
-    }
-    var str = '' + this;
-    count = +count;
-    if (count != count) {
-      count = 0;
-    }
-    if (count < 0) {
-      throw new RangeError('repeat count must be non-negative');
-    }
-    if (count == Infinity) {
-      throw new RangeError('repeat count must be less than infinity');
-    }
-    count = Math.floor(count);
-    if (str.length == 0 || count == 0) {
-      return '';
-    }
-    // Ensuring count is a 31-bit integer allows us to heavily optimize the
-    // main part. But anyway, most current (August 2014) browsers can't handle
-    // strings 1 << 28 chars or longer, so:
-    if (str.length * count >= 1 << 28) {
-      throw new RangeError('repeat count must not overflow maximum string size');
-    }
-    var maxCount = str.length * count;
-    count = Math.floor(Math.log(count) / Math.log(2));
-    while (count) {
-       str += str;
-       count--;
-    }
-    str += str.substring(0, maxCount - str.length);
-    return str;
-  }
-}
diff --git a/ctest/printj.js b/ctest/printj.js
index a2a38d6..ff000bb 100644
--- a/ctest/printj.js
+++ b/ctest/printj.js
@@ -25,7 +25,7 @@ var PRINTJ;
 	/*jshint ignore:end */
 }(function(PRINTJ) {
 
-PRINTJ.version = '1.1.2';
+PRINTJ.version = '1.2.1';
 
 function tokenize(fmt) {
 	var out = [];
@@ -149,14 +149,6 @@ function tokenize(fmt) {
 	return out;
 }
 
-//#define PAD_(x,c) (x >= 0 ? new Array(((x)|0) + 1).join((c)) : "")
-var padstr = {
-	" ": "                                 ",
-	"0": "000000000000000000000000000000000",
-	"7": "777777777777777777777777777777777",
-	"f": "fffffffffffffffffffffffffffffffff"
-};
-
 /*global process:true, util:true, require:true */
 if(typeof process !== 'undefined' && !!process.versions && !!process.versions.node) util=require("util");
 var u_inspect = (typeof util != 'undefined') ? util.inspect : JSON.stringify;
@@ -208,7 +200,7 @@ function doit(t, args) {
 				/* only valid flag is "-" for left justification */
 				O = String(arg);
 				if( prec >= 0) O = O.substr(0,  prec);
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 			/* first char of string or convert */
@@ -223,7 +215,7 @@ function doit(t, args) {
 					case "string": O = arg.charAt(0); break;
 					default: O = String(arg).charAt(0);
 				}
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 			/* int diDuUoOxXbB */
@@ -308,10 +300,10 @@ function doit(t, args) {
 			/* boolean (extension) */
 			case /*Y*/  89:
 			case /*y*/ 121:
-				O = Boolean(arg) ? (alt ? "yes" : "true") : (alt ? "no" : "false");
+				O = (arg) ? (alt ? "yes" : "true") : (alt ? "no" : "false");
 				if(c == /*Y*/ 89) O = O.toUpperCase();
 				if( prec >= 0) O = O.substr(0,  prec);
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 		}
@@ -373,16 +365,16 @@ function doit(t, args) {
 				if(radix == 16 || radix == -16) {
 					O = (Vnum>>>0).toString(16);
 					Vnum = Math.floor((Vnum - (Vnum >>> 0)) / Math.pow(2,32));
-					O = (Vnum>>>0).toString(16) + (8 - O.length >= 0 ? padstr[ "0"].substr(0,8 - O.length) : "") + O;
-					O = (16 - O.length >= 0 ? padstr[ "f"].substr(0,16 - O.length) : "") + O;
+					O = (Vnum>>>0).toString(16) + (8 - O.length >= 0 ?  "0".repeat(8 - O.length) : "") + O;
+					O = (16 - O.length >= 0 ?  "f".repeat(16 - O.length) : "") + O;
 					if(radix == 16) O = O.toUpperCase();
 				} else if(radix == 8) {
 					O = (Vnum>>>0).toString(8);
-					O = (10 - O.length >= 0 ? padstr[ "0"].substr(0,10 - O.length) : "") + O;
+					O = (10 - O.length >= 0 ?  "0".repeat(10 - O.length) : "") + O;
 					Vnum = Math.floor((Vnum - ((Vnum >>> 0)&0x3FFFFFFF)) / Math.pow(2,30));
 					O = (Vnum>>>0).toString(8) + O.substr(O.length - 10);
 					O = O.substr(O.length - 20);
-					O = "1" + (21 - O.length >= 0 ? padstr[ "7"].substr(0,21 - O.length) : "") + O;
+					O = "1" + (21 - O.length >= 0 ?  "7".repeat(21 - O.length) : "") + O;
 				} else {
 					Vnum = (-Vnum) % 1e16;
 					var d1 = [1,8,4,4,6,7,4,4,0,7,3,7,0,9,5,5,1,6,1,6];
@@ -403,8 +395,8 @@ function doit(t, args) {
 			if(prec ===0 && O == "0" && !(radix == 8 && alt)) O = ""; /* bail out */
 			else {
 				if(O.length < prec + (O.substr(0,1) == "-" ? 1 : 0)) {
-					if(O.substr(0,1) != "-") O = (prec - O.length >= 0 ? padstr[ "0"].substr(0,prec - O.length) : "") + O;
-					else O = O.substr(0,1) + (prec + 1 - O.length >= 0 ? padstr[ "0"].substr(0,prec + 1 - O.length) : "") + O.substr(1);
+					if(O.substr(0,1) != "-") O = (prec - O.length >= 0 ?  "0".repeat(prec - O.length) : "") + O;
+					else O = O.substr(0,1) + (prec + 1 - O.length >= 0 ?  "0".repeat(prec + 1 - O.length) : "") + O.substr(1);
 				}
 
 				/* add prefix for # form */
@@ -425,10 +417,10 @@ function doit(t, args) {
 			if(width > 0) {
 				if(O.length < width) {
 					if(flags.indexOf("-") > -1) {
-						O = O + ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "");
+						O = O + ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "");
 					} else if(flags.indexOf("0") > -1 && prec < 0 && O.length > 0) {
-						if(prec > O.length) O = ((prec - O.length) >= 0 ? padstr[ "0"].substr(0,(prec - O.length)) : "") + O;
-						pad = ((width - O.length) >= 0 ? padstr[ (prec > 0 ? " " : "0")].substr(0,(width - O.length)) : "");
+						if(prec > O.length) O = ((prec - O.length) >= 0 ?  "0".repeat((prec - O.length)) : "") + O;
+						pad = ((width - O.length) >= 0 ?  (prec > 0 ? " " : "0").repeat((width - O.length)) : "");
 						if(O.charCodeAt(0) < 48) {
 							if(O.charAt(2).toLowerCase() == "x") O = O.substr(0,3) + pad + O.substring(3);
 							else O = O.substr(0,1) + pad + O.substring(1);
@@ -436,7 +428,7 @@ function doit(t, args) {
 						else if(O.charAt(1).toLowerCase() == "x") O = O.substr(0,2) + pad + O.substring(2);
 						else O = pad + O;
 					} else {
-						O = ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "") + O;
+						O = ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "") + O;
 					}
 				}
 			}
@@ -483,8 +475,8 @@ function doit(t, args) {
 						O = Vnum.toExponential(20);
 						E = +O.substr(O.indexOf("e")+1);
 						O = O.charAt(0) + O.substr(2,O.indexOf("e")-2);
-						O = O + (E - O.length + 1 >= 0 ? padstr[ "0"].substr(0,E - O.length + 1) : "");
-						if(alt || (prec > 0 && isnum !== 11)) O = O + "." + (prec >= 0 ? padstr[ "0"].substr(0,prec) : "");
+						O = O + (E - O.length + 1 >= 0 ?  "0".repeat(E - O.length + 1) : "");
+						if(alt || (prec > 0 && isnum !== 11)) O = O + "." + (prec >= 0 ?  "0".repeat(prec) : "");
 						break;
 
 					/* e/E exponential */
@@ -498,7 +490,7 @@ function doit(t, args) {
 
 					/* a/A hex */
 					case 4:
-						if(Vnum===0){O= "0x0"+((alt||prec>0)?"."+(prec >= 0 ? padstr["0"].substr(0,prec) : ""):"")+"p+0"; break;}
+						if(Vnum===0){O= "0x0"+((alt||prec>0)?"."+(prec >= 0 ? "0".repeat(prec) : ""):"")+"p+0"; break;}
 						O = Vnum.toString(16);
 						/* First char 0-9 */
 						var ac = O.charCodeAt(0);
@@ -545,11 +537,11 @@ function doit(t, args) {
 							if(prec > 0) {
 								O = O.substr(0, prec + 2);
 								if(O.length < prec + 2) {
-									if(O.charCodeAt(0) < 48) O = O.charAt(0) + ((prec + 2 - O.length) >= 0 ? padstr[ "0"].substr(0,(prec + 2 - O.length)) : "") + O.substr(1);
-									else O += ((prec + 2 - O.length) >= 0 ? padstr[ "0"].substr(0,(prec + 2 - O.length)) : "");
+									if(O.charCodeAt(0) < 48) O = O.charAt(0) + ((prec + 2 - O.length) >= 0 ?  "0".repeat((prec + 2 - O.length)) : "") + O.substr(1);
+									else O += ((prec + 2 - O.length) >= 0 ?  "0".repeat((prec + 2 - O.length)) : "");
 								}
 							} else if(prec === 0) O = O.charAt(0) + (alt ? "." : "");
-						} else if(prec > 0) O = O + "." + (prec >= 0 ? padstr["0"].substr(0,prec) : "");
+						} else if(prec > 0) O = O + "." + (prec >= 0 ? "0".repeat(prec) : "");
 						else if(alt) O = O + ".";
 						O = "0x" + O + "p" + (E>=0 ? "+" + E : E);
 						break;
@@ -566,9 +558,9 @@ function doit(t, args) {
 			/* width */
 			if(width > O.length) {
 				if(flags.indexOf("-") > -1) {
-					O = O + ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "");
+					O = O + ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "");
 				} else if(flags.indexOf("0") > -1 && O.length > 0 && isf) {
-					pad = ((width - O.length) >= 0 ? padstr[ "0"].substr(0,(width - O.length)) : "");
+					pad = ((width - O.length) >= 0 ?  "0".repeat((width - O.length)) : "");
 					if(O.charCodeAt(0) < 48) {
 						if(O.charAt(2).toLowerCase() == "x") O = O.substr(0,3) + pad + O.substring(3);
 						else O = O.substr(0,1) + pad + O.substring(1);
@@ -576,7 +568,7 @@ function doit(t, args) {
 					else if(O.charAt(1).toLowerCase() == "x") O = O.substr(0,2) + pad + O.substring(2);
 					else O = pad + O;
 				} else {
-					O = ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "") + O;
+					O = ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "") + O;
 				}
 			}
 			if(c < 96) O = O.toUpperCase();
diff --git a/ctest/shim.js b/ctest/shim.js
index e3d7840..4493b85 100644
--- a/ctest/shim.js
+++ b/ctest/shim.js
@@ -235,3 +235,42 @@ if (typeof ArrayBuffer !== 'undefined' && !ArrayBuffer.prototype.slice) {
     return target;
   };
 }
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat
+if (!String.prototype.repeat) {
+  String.prototype.repeat = function(count) {
+    'use strict';
+    if (this == null) {
+      throw new TypeError('can\'t convert ' + this + ' to object');
+    }
+    var str = '' + this;
+    count = +count;
+    if (count != count) {
+      count = 0;
+    }
+    if (count < 0) {
+      throw new RangeError('repeat count must be non-negative');
+    }
+    if (count == Infinity) {
+      throw new RangeError('repeat count must be less than infinity');
+    }
+    count = Math.floor(count);
+    if (str.length == 0 || count == 0) {
+      return '';
+    }
+    // Ensuring count is a 31-bit integer allows us to heavily optimize the
+    // main part. But anyway, most current (August 2014) browsers can't handle
+    // strings 1 << 28 chars or longer, so:
+    if (str.length * count >= 1 << 28) {
+      throw new RangeError('repeat count must not overflow maximum string size');
+    }
+    var maxCount = str.length * count;
+    count = Math.floor(Math.log(count) / Math.log(2));
+    while (count) {
+       str += str;
+       count--;
+    }
+    str += str.substring(0, maxCount - str.length);
+    return str;
+  };
+}
diff --git a/ctest/test.js b/ctest/test.js
index b073a51..ef30c84 100644
--- a/ctest/test.js
+++ b/ctest/test.js
@@ -190,4 +190,7 @@ describe('special cases', function() {
 		assert.equal(sprintf("|%*.*s|", 4,  0, "sheetjs"), "|    |");
 		assert.equal(sprintf("|%*.*s|", 4, -1, "sheetjs"), "|sheetjs|");
 	});
+	it('handles long strings', function() {
+		for(var i = 10; i <= 1000; i+= 10) assert.equal(sprintf("%" + i + "s", "abc").length, i);
+	});
 });
diff --git a/lib/loop_code.mjs b/lib/loop_code.mjs
index decfc8c..19bd6fb 100644
--- a/lib/loop_code.mjs
+++ b/lib/loop_code.mjs
@@ -7,7 +7,7 @@
 
 var PRINTJ/*:PRINTJModule*/ = /*::(*/{}/*:: :any)*/;
 
-PRINTJ.version = '1.2.0';
+PRINTJ.version = '1.2.1';
 
 export const version = PRINTJ.version;
 
@@ -133,14 +133,6 @@ function tokenize(fmt/*:string*/)/*:ParsedFmt*/ {
 	return out;
 }
 
-//#define PAD_(x,c) (x >= 0 ? new Array(((x)|0) + 1).join((c)) : "")
-var padstr/*:{[s:string]:string}*/ = {
-	" ": "                                 ",
-	"0": "000000000000000000000000000000000",
-	"7": "777777777777777777777777777777777",
-	"f": "fffffffffffffffffffffffffffffffff"
-};
-
 var u_inspect/*:(o:any)=>string*/ = JSON.stringify;
 
 function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
@@ -190,7 +182,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 				/* only valid flag is "-" for left justification */
 				O = String(arg);
 				if( prec >= 0) O = O.substr(0,  prec);
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 			/* first char of string or convert */
@@ -205,7 +197,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 					case "string": O = /*::(*/arg/*:: :string)*/.charAt(0); break;
 					default: O = String(arg).charAt(0);
 				}
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 			/* int diDuUoOxXbB */
@@ -293,7 +285,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 				O = (arg) ? (alt ? "yes" : "true") : (alt ? "no" : "false");
 				if(c == /*Y*/ 89) O = O.toUpperCase();
 				if( prec >= 0) O = O.substr(0,  prec);
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 		}
@@ -355,16 +347,16 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 				if(radix == 16 || radix == -16) {
 					O = (Vnum>>>0).toString(16);
 					Vnum = Math.floor((Vnum - (Vnum >>> 0)) / Math.pow(2,32));
-					O = (Vnum>>>0).toString(16) + (8 - O.length >= 0 ? padstr[ "0"].substr(0,8 - O.length) : "") + O;
-					O = (16 - O.length >= 0 ? padstr[ "f"].substr(0,16 - O.length) : "") + O;
+					O = (Vnum>>>0).toString(16) + (8 - O.length >= 0 ?  "0".repeat(8 - O.length) : "") + O;
+					O = (16 - O.length >= 0 ?  "f".repeat(16 - O.length) : "") + O;
 					if(radix == 16) O = O.toUpperCase();
 				} else if(radix == 8) {
 					O = (Vnum>>>0).toString(8);
-					O = (10 - O.length >= 0 ? padstr[ "0"].substr(0,10 - O.length) : "") + O;
+					O = (10 - O.length >= 0 ?  "0".repeat(10 - O.length) : "") + O;
 					Vnum = Math.floor((Vnum - ((Vnum >>> 0)&0x3FFFFFFF)) / Math.pow(2,30));
 					O = (Vnum>>>0).toString(8) + O.substr(O.length - 10);
 					O = O.substr(O.length - 20);
-					O = "1" + (21 - O.length >= 0 ? padstr[ "7"].substr(0,21 - O.length) : "") + O;
+					O = "1" + (21 - O.length >= 0 ?  "7".repeat(21 - O.length) : "") + O;
 				} else {
 					Vnum = (-Vnum) % 1e16;
 					var d1/*:Array<number>*/ = [1,8,4,4,6,7,4,4,0,7,3,7,0,9,5,5,1,6,1,6];
@@ -385,8 +377,8 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 			if(prec ===0 && O == "0" && !(radix == 8 && alt)) O = ""; /* bail out */
 			else {
 				if(O.length < prec + (O.substr(0,1) == "-" ? 1 : 0)) {
-					if(O.substr(0,1) != "-") O = (prec - O.length >= 0 ? padstr[ "0"].substr(0,prec - O.length) : "") + O;
-					else O = O.substr(0,1) + (prec + 1 - O.length >= 0 ? padstr[ "0"].substr(0,prec + 1 - O.length) : "") + O.substr(1);
+					if(O.substr(0,1) != "-") O = (prec - O.length >= 0 ?  "0".repeat(prec - O.length) : "") + O;
+					else O = O.substr(0,1) + (prec + 1 - O.length >= 0 ?  "0".repeat(prec + 1 - O.length) : "") + O.substr(1);
 				}
 
 				/* add prefix for # form */
@@ -407,10 +399,10 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 			if(width > 0) {
 				if(O.length < width) {
 					if(flags.indexOf("-") > -1) {
-						O = O + ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "");
+						O = O + ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "");
 					} else if(flags.indexOf("0") > -1 && prec < 0 && O.length > 0) {
-						if(prec > O.length) O = ((prec - O.length) >= 0 ? padstr[ "0"].substr(0,(prec - O.length)) : "") + O;
-						pad = ((width - O.length) >= 0 ? padstr[ (prec > 0 ? " " : "0")].substr(0,(width - O.length)) : "");
+						if(prec > O.length) O = ((prec - O.length) >= 0 ?  "0".repeat((prec - O.length)) : "") + O;
+						pad = ((width - O.length) >= 0 ?  (prec > 0 ? " " : "0").repeat((width - O.length)) : "");
 						if(O.charCodeAt(0) < 48) {
 							if(O.charAt(2).toLowerCase() == "x") O = O.substr(0,3) + pad + O.substring(3);
 							else O = O.substr(0,1) + pad + O.substring(1);
@@ -418,7 +410,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 						else if(O.charAt(1).toLowerCase() == "x") O = O.substr(0,2) + pad + O.substring(2);
 						else O = pad + O;
 					} else {
-						O = ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "") + O;
+						O = ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "") + O;
 					}
 				}
 			}
@@ -465,8 +457,8 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 						O = Vnum.toExponential(20);
 						E = +O.substr(O.indexOf("e")+1);
 						O = O.charAt(0) + O.substr(2,O.indexOf("e")-2);
-						O = O + (E - O.length + 1 >= 0 ? padstr[ "0"].substr(0,E - O.length + 1) : "");
-						if(alt || (prec > 0 && isnum !== 11)) O = O + "." + (prec >= 0 ? padstr[ "0"].substr(0,prec) : "");
+						O = O + (E - O.length + 1 >= 0 ?  "0".repeat(E - O.length + 1) : "");
+						if(alt || (prec > 0 && isnum !== 11)) O = O + "." + (prec >= 0 ?  "0".repeat(prec) : "");
 						break;
 
 					/* e/E exponential */
@@ -480,7 +472,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 
 					/* a/A hex */
 					case 4:
-						if(Vnum===0){O= "0x0"+((alt||prec>0)?"."+(prec >= 0 ? padstr["0"].substr(0,prec) : ""):"")+"p+0"; break;}
+						if(Vnum===0){O= "0x0"+((alt||prec>0)?"."+(prec >= 0 ? "0".repeat(prec) : ""):"")+"p+0"; break;}
 						O = Vnum.toString(16);
 						/* First char 0-9 */
 						var ac/*:number*/ = O.charCodeAt(0);
@@ -527,11 +519,11 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 							if(prec > 0) {
 								O = O.substr(0, prec + 2);
 								if(O.length < prec + 2) {
-									if(O.charCodeAt(0) < 48) O = O.charAt(0) + ((prec + 2 - O.length) >= 0 ? padstr[ "0"].substr(0,(prec + 2 - O.length)) : "") + O.substr(1);
-									else O += ((prec + 2 - O.length) >= 0 ? padstr[ "0"].substr(0,(prec + 2 - O.length)) : "");
+									if(O.charCodeAt(0) < 48) O = O.charAt(0) + ((prec + 2 - O.length) >= 0 ?  "0".repeat((prec + 2 - O.length)) : "") + O.substr(1);
+									else O += ((prec + 2 - O.length) >= 0 ?  "0".repeat((prec + 2 - O.length)) : "");
 								}
 							} else if(prec === 0) O = O.charAt(0) + (alt ? "." : "");
-						} else if(prec > 0) O = O + "." + (prec >= 0 ? padstr["0"].substr(0,prec) : "");
+						} else if(prec > 0) O = O + "." + (prec >= 0 ? "0".repeat(prec) : "");
 						else if(alt) O = O + ".";
 						O = "0x" + O + "p" + (E>=0 ? "+" + E : E);
 						break;
@@ -548,9 +540,9 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 			/* width */
 			if(width > O.length) {
 				if(flags.indexOf("-") > -1) {
-					O = O + ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "");
+					O = O + ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "");
 				} else if(flags.indexOf("0") > -1 && O.length > 0 && isf) {
-					pad = ((width - O.length) >= 0 ? padstr[ "0"].substr(0,(width - O.length)) : "");
+					pad = ((width - O.length) >= 0 ?  "0".repeat((width - O.length)) : "");
 					if(O.charCodeAt(0) < 48) {
 						if(O.charAt(2).toLowerCase() == "x") O = O.substr(0,3) + pad + O.substring(3);
 						else O = O.substr(0,1) + pad + O.substring(1);
@@ -558,7 +550,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 					else if(O.charAt(1).toLowerCase() == "x") O = O.substr(0,2) + pad + O.substring(2);
 					else O = pad + O;
 				} else {
-					O = ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "") + O;
+					O = ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "") + O;
 				}
 			}
 			if(c < 96) O = O.toUpperCase();
diff --git a/package.json b/package.json
index 5bfc17b..50d9ddf 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
 	"name": "printj",
-	"version": "1.2.0",
+	"version": "1.2.1",
 	"author": "sheetjs",
 	"description": "Pure-JS printf",
 	"keywords": [
diff --git a/printj.flow.js b/printj.flow.js
index f912739..ecf88bf 100644
--- a/printj.flow.js
+++ b/printj.flow.js
@@ -28,7 +28,7 @@ var PRINTJ/*:PRINTJModule*/;
 	/*jshint ignore:end */
 }(function(PRINTJ/*:PRINTJModule*/) {
 
-PRINTJ.version = '1.2.0';
+PRINTJ.version = '1.2.1';
 
 function tokenize(fmt/*:string*/)/*:ParsedFmt*/ {
 	var out/*:ParsedFmt*/ = [];
@@ -152,14 +152,6 @@ function tokenize(fmt/*:string*/)/*:ParsedFmt*/ {
 	return out;
 }
 
-//#define PAD_(x,c) (x >= 0 ? new Array(((x)|0) + 1).join((c)) : "")
-var padstr/*:{[s:string]:string}*/ = {
-	" ": "                                 ",
-	"0": "000000000000000000000000000000000",
-	"7": "777777777777777777777777777777777",
-	"f": "fffffffffffffffffffffffffffffffff"
-};
-
 /*:: var util = require('util'); */
 /*global process:true, util:true, require:true */
 if(typeof process !== 'undefined' && !!process.versions && !!process.versions.node) util=require("util");
@@ -212,7 +204,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 				/* only valid flag is "-" for left justification */
 				O = String(arg);
 				if( prec >= 0) O = O.substr(0,  prec);
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 			/* first char of string or convert */
@@ -227,7 +219,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 					case "string": O = /*::(*/arg/*:: :string)*/.charAt(0); break;
 					default: O = String(arg).charAt(0);
 				}
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 			/* int diDuUoOxXbB */
@@ -315,7 +307,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 				O = (arg) ? (alt ? "yes" : "true") : (alt ? "no" : "false");
 				if(c == /*Y*/ 89) O = O.toUpperCase();
 				if( prec >= 0) O = O.substr(0,  prec);
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 		}
@@ -377,16 +369,16 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 				if(radix == 16 || radix == -16) {
 					O = (Vnum>>>0).toString(16);
 					Vnum = Math.floor((Vnum - (Vnum >>> 0)) / Math.pow(2,32));
-					O = (Vnum>>>0).toString(16) + (8 - O.length >= 0 ? padstr[ "0"].substr(0,8 - O.length) : "") + O;
-					O = (16 - O.length >= 0 ? padstr[ "f"].substr(0,16 - O.length) : "") + O;
+					O = (Vnum>>>0).toString(16) + (8 - O.length >= 0 ?  "0".repeat(8 - O.length) : "") + O;
+					O = (16 - O.length >= 0 ?  "f".repeat(16 - O.length) : "") + O;
 					if(radix == 16) O = O.toUpperCase();
 				} else if(radix == 8) {
 					O = (Vnum>>>0).toString(8);
-					O = (10 - O.length >= 0 ? padstr[ "0"].substr(0,10 - O.length) : "") + O;
+					O = (10 - O.length >= 0 ?  "0".repeat(10 - O.length) : "") + O;
 					Vnum = Math.floor((Vnum - ((Vnum >>> 0)&0x3FFFFFFF)) / Math.pow(2,30));
 					O = (Vnum>>>0).toString(8) + O.substr(O.length - 10);
 					O = O.substr(O.length - 20);
-					O = "1" + (21 - O.length >= 0 ? padstr[ "7"].substr(0,21 - O.length) : "") + O;
+					O = "1" + (21 - O.length >= 0 ?  "7".repeat(21 - O.length) : "") + O;
 				} else {
 					Vnum = (-Vnum) % 1e16;
 					var d1/*:Array<number>*/ = [1,8,4,4,6,7,4,4,0,7,3,7,0,9,5,5,1,6,1,6];
@@ -407,8 +399,8 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 			if(prec ===0 && O == "0" && !(radix == 8 && alt)) O = ""; /* bail out */
 			else {
 				if(O.length < prec + (O.substr(0,1) == "-" ? 1 : 0)) {
-					if(O.substr(0,1) != "-") O = (prec - O.length >= 0 ? padstr[ "0"].substr(0,prec - O.length) : "") + O;
-					else O = O.substr(0,1) + (prec + 1 - O.length >= 0 ? padstr[ "0"].substr(0,prec + 1 - O.length) : "") + O.substr(1);
+					if(O.substr(0,1) != "-") O = (prec - O.length >= 0 ?  "0".repeat(prec - O.length) : "") + O;
+					else O = O.substr(0,1) + (prec + 1 - O.length >= 0 ?  "0".repeat(prec + 1 - O.length) : "") + O.substr(1);
 				}
 
 				/* add prefix for # form */
@@ -429,10 +421,10 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 			if(width > 0) {
 				if(O.length < width) {
 					if(flags.indexOf("-") > -1) {
-						O = O + ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "");
+						O = O + ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "");
 					} else if(flags.indexOf("0") > -1 && prec < 0 && O.length > 0) {
-						if(prec > O.length) O = ((prec - O.length) >= 0 ? padstr[ "0"].substr(0,(prec - O.length)) : "") + O;
-						pad = ((width - O.length) >= 0 ? padstr[ (prec > 0 ? " " : "0")].substr(0,(width - O.length)) : "");
+						if(prec > O.length) O = ((prec - O.length) >= 0 ?  "0".repeat((prec - O.length)) : "") + O;
+						pad = ((width - O.length) >= 0 ?  (prec > 0 ? " " : "0").repeat((width - O.length)) : "");
 						if(O.charCodeAt(0) < 48) {
 							if(O.charAt(2).toLowerCase() == "x") O = O.substr(0,3) + pad + O.substring(3);
 							else O = O.substr(0,1) + pad + O.substring(1);
@@ -440,7 +432,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 						else if(O.charAt(1).toLowerCase() == "x") O = O.substr(0,2) + pad + O.substring(2);
 						else O = pad + O;
 					} else {
-						O = ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "") + O;
+						O = ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "") + O;
 					}
 				}
 			}
@@ -487,8 +479,8 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 						O = Vnum.toExponential(20);
 						E = +O.substr(O.indexOf("e")+1);
 						O = O.charAt(0) + O.substr(2,O.indexOf("e")-2);
-						O = O + (E - O.length + 1 >= 0 ? padstr[ "0"].substr(0,E - O.length + 1) : "");
-						if(alt || (prec > 0 && isnum !== 11)) O = O + "." + (prec >= 0 ? padstr[ "0"].substr(0,prec) : "");
+						O = O + (E - O.length + 1 >= 0 ?  "0".repeat(E - O.length + 1) : "");
+						if(alt || (prec > 0 && isnum !== 11)) O = O + "." + (prec >= 0 ?  "0".repeat(prec) : "");
 						break;
 
 					/* e/E exponential */
@@ -502,7 +494,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 
 					/* a/A hex */
 					case 4:
-						if(Vnum===0){O= "0x0"+((alt||prec>0)?"."+(prec >= 0 ? padstr["0"].substr(0,prec) : ""):"")+"p+0"; break;}
+						if(Vnum===0){O= "0x0"+((alt||prec>0)?"."+(prec >= 0 ? "0".repeat(prec) : ""):"")+"p+0"; break;}
 						O = Vnum.toString(16);
 						/* First char 0-9 */
 						var ac/*:number*/ = O.charCodeAt(0);
@@ -549,11 +541,11 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 							if(prec > 0) {
 								O = O.substr(0, prec + 2);
 								if(O.length < prec + 2) {
-									if(O.charCodeAt(0) < 48) O = O.charAt(0) + ((prec + 2 - O.length) >= 0 ? padstr[ "0"].substr(0,(prec + 2 - O.length)) : "") + O.substr(1);
-									else O += ((prec + 2 - O.length) >= 0 ? padstr[ "0"].substr(0,(prec + 2 - O.length)) : "");
+									if(O.charCodeAt(0) < 48) O = O.charAt(0) + ((prec + 2 - O.length) >= 0 ?  "0".repeat((prec + 2 - O.length)) : "") + O.substr(1);
+									else O += ((prec + 2 - O.length) >= 0 ?  "0".repeat((prec + 2 - O.length)) : "");
 								}
 							} else if(prec === 0) O = O.charAt(0) + (alt ? "." : "");
-						} else if(prec > 0) O = O + "." + (prec >= 0 ? padstr["0"].substr(0,prec) : "");
+						} else if(prec > 0) O = O + "." + (prec >= 0 ? "0".repeat(prec) : "");
 						else if(alt) O = O + ".";
 						O = "0x" + O + "p" + (E>=0 ? "+" + E : E);
 						break;
@@ -570,9 +562,9 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 			/* width */
 			if(width > O.length) {
 				if(flags.indexOf("-") > -1) {
-					O = O + ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "");
+					O = O + ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "");
 				} else if(flags.indexOf("0") > -1 && O.length > 0 && isf) {
-					pad = ((width - O.length) >= 0 ? padstr[ "0"].substr(0,(width - O.length)) : "");
+					pad = ((width - O.length) >= 0 ?  "0".repeat((width - O.length)) : "");
 					if(O.charCodeAt(0) < 48) {
 						if(O.charAt(2).toLowerCase() == "x") O = O.substr(0,3) + pad + O.substring(3);
 						else O = O.substr(0,1) + pad + O.substring(1);
@@ -580,7 +572,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 					else if(O.charAt(1).toLowerCase() == "x") O = O.substr(0,2) + pad + O.substring(2);
 					else O = pad + O;
 				} else {
-					O = ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "") + O;
+					O = ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "") + O;
 				}
 			}
 			if(c < 96) O = O.toUpperCase();
diff --git a/printj.js b/printj.js
index f01f0bf..ff000bb 100644
--- a/printj.js
+++ b/printj.js
@@ -25,7 +25,7 @@ var PRINTJ;
 	/*jshint ignore:end */
 }(function(PRINTJ) {
 
-PRINTJ.version = '1.2.0';
+PRINTJ.version = '1.2.1';
 
 function tokenize(fmt) {
 	var out = [];
@@ -149,14 +149,6 @@ function tokenize(fmt) {
 	return out;
 }
 
-//#define PAD_(x,c) (x >= 0 ? new Array(((x)|0) + 1).join((c)) : "")
-var padstr = {
-	" ": "                                 ",
-	"0": "000000000000000000000000000000000",
-	"7": "777777777777777777777777777777777",
-	"f": "fffffffffffffffffffffffffffffffff"
-};
-
 /*global process:true, util:true, require:true */
 if(typeof process !== 'undefined' && !!process.versions && !!process.versions.node) util=require("util");
 var u_inspect = (typeof util != 'undefined') ? util.inspect : JSON.stringify;
@@ -208,7 +200,7 @@ function doit(t, args) {
 				/* only valid flag is "-" for left justification */
 				O = String(arg);
 				if( prec >= 0) O = O.substr(0,  prec);
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 			/* first char of string or convert */
@@ -223,7 +215,7 @@ function doit(t, args) {
 					case "string": O = arg.charAt(0); break;
 					default: O = String(arg).charAt(0);
 				}
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 			/* int diDuUoOxXbB */
@@ -311,7 +303,7 @@ function doit(t, args) {
 				O = (arg) ? (alt ? "yes" : "true") : (alt ? "no" : "false");
 				if(c == /*Y*/ 89) O = O.toUpperCase();
 				if( prec >= 0) O = O.substr(0,  prec);
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 		}
@@ -373,16 +365,16 @@ function doit(t, args) {
 				if(radix == 16 || radix == -16) {
 					O = (Vnum>>>0).toString(16);
 					Vnum = Math.floor((Vnum - (Vnum >>> 0)) / Math.pow(2,32));
-					O = (Vnum>>>0).toString(16) + (8 - O.length >= 0 ? padstr[ "0"].substr(0,8 - O.length) : "") + O;
-					O = (16 - O.length >= 0 ? padstr[ "f"].substr(0,16 - O.length) : "") + O;
+					O = (Vnum>>>0).toString(16) + (8 - O.length >= 0 ?  "0".repeat(8 - O.length) : "") + O;
+					O = (16 - O.length >= 0 ?  "f".repeat(16 - O.length) : "") + O;
 					if(radix == 16) O = O.toUpperCase();
 				} else if(radix == 8) {
 					O = (Vnum>>>0).toString(8);
-					O = (10 - O.length >= 0 ? padstr[ "0"].substr(0,10 - O.length) : "") + O;
+					O = (10 - O.length >= 0 ?  "0".repeat(10 - O.length) : "") + O;
 					Vnum = Math.floor((Vnum - ((Vnum >>> 0)&0x3FFFFFFF)) / Math.pow(2,30));
 					O = (Vnum>>>0).toString(8) + O.substr(O.length - 10);
 					O = O.substr(O.length - 20);
-					O = "1" + (21 - O.length >= 0 ? padstr[ "7"].substr(0,21 - O.length) : "") + O;
+					O = "1" + (21 - O.length >= 0 ?  "7".repeat(21 - O.length) : "") + O;
 				} else {
 					Vnum = (-Vnum) % 1e16;
 					var d1 = [1,8,4,4,6,7,4,4,0,7,3,7,0,9,5,5,1,6,1,6];
@@ -403,8 +395,8 @@ function doit(t, args) {
 			if(prec ===0 && O == "0" && !(radix == 8 && alt)) O = ""; /* bail out */
 			else {
 				if(O.length < prec + (O.substr(0,1) == "-" ? 1 : 0)) {
-					if(O.substr(0,1) != "-") O = (prec - O.length >= 0 ? padstr[ "0"].substr(0,prec - O.length) : "") + O;
-					else O = O.substr(0,1) + (prec + 1 - O.length >= 0 ? padstr[ "0"].substr(0,prec + 1 - O.length) : "") + O.substr(1);
+					if(O.substr(0,1) != "-") O = (prec - O.length >= 0 ?  "0".repeat(prec - O.length) : "") + O;
+					else O = O.substr(0,1) + (prec + 1 - O.length >= 0 ?  "0".repeat(prec + 1 - O.length) : "") + O.substr(1);
 				}
 
 				/* add prefix for # form */
@@ -425,10 +417,10 @@ function doit(t, args) {
 			if(width > 0) {
 				if(O.length < width) {
 					if(flags.indexOf("-") > -1) {
-						O = O + ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "");
+						O = O + ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "");
 					} else if(flags.indexOf("0") > -1 && prec < 0 && O.length > 0) {
-						if(prec > O.length) O = ((prec - O.length) >= 0 ? padstr[ "0"].substr(0,(prec - O.length)) : "") + O;
-						pad = ((width - O.length) >= 0 ? padstr[ (prec > 0 ? " " : "0")].substr(0,(width - O.length)) : "");
+						if(prec > O.length) O = ((prec - O.length) >= 0 ?  "0".repeat((prec - O.length)) : "") + O;
+						pad = ((width - O.length) >= 0 ?  (prec > 0 ? " " : "0").repeat((width - O.length)) : "");
 						if(O.charCodeAt(0) < 48) {
 							if(O.charAt(2).toLowerCase() == "x") O = O.substr(0,3) + pad + O.substring(3);
 							else O = O.substr(0,1) + pad + O.substring(1);
@@ -436,7 +428,7 @@ function doit(t, args) {
 						else if(O.charAt(1).toLowerCase() == "x") O = O.substr(0,2) + pad + O.substring(2);
 						else O = pad + O;
 					} else {
-						O = ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "") + O;
+						O = ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "") + O;
 					}
 				}
 			}
@@ -483,8 +475,8 @@ function doit(t, args) {
 						O = Vnum.toExponential(20);
 						E = +O.substr(O.indexOf("e")+1);
 						O = O.charAt(0) + O.substr(2,O.indexOf("e")-2);
-						O = O + (E - O.length + 1 >= 0 ? padstr[ "0"].substr(0,E - O.length + 1) : "");
-						if(alt || (prec > 0 && isnum !== 11)) O = O + "." + (prec >= 0 ? padstr[ "0"].substr(0,prec) : "");
+						O = O + (E - O.length + 1 >= 0 ?  "0".repeat(E - O.length + 1) : "");
+						if(alt || (prec > 0 && isnum !== 11)) O = O + "." + (prec >= 0 ?  "0".repeat(prec) : "");
 						break;
 
 					/* e/E exponential */
@@ -498,7 +490,7 @@ function doit(t, args) {
 
 					/* a/A hex */
 					case 4:
-						if(Vnum===0){O= "0x0"+((alt||prec>0)?"."+(prec >= 0 ? padstr["0"].substr(0,prec) : ""):"")+"p+0"; break;}
+						if(Vnum===0){O= "0x0"+((alt||prec>0)?"."+(prec >= 0 ? "0".repeat(prec) : ""):"")+"p+0"; break;}
 						O = Vnum.toString(16);
 						/* First char 0-9 */
 						var ac = O.charCodeAt(0);
@@ -545,11 +537,11 @@ function doit(t, args) {
 							if(prec > 0) {
 								O = O.substr(0, prec + 2);
 								if(O.length < prec + 2) {
-									if(O.charCodeAt(0) < 48) O = O.charAt(0) + ((prec + 2 - O.length) >= 0 ? padstr[ "0"].substr(0,(prec + 2 - O.length)) : "") + O.substr(1);
-									else O += ((prec + 2 - O.length) >= 0 ? padstr[ "0"].substr(0,(prec + 2 - O.length)) : "");
+									if(O.charCodeAt(0) < 48) O = O.charAt(0) + ((prec + 2 - O.length) >= 0 ?  "0".repeat((prec + 2 - O.length)) : "") + O.substr(1);
+									else O += ((prec + 2 - O.length) >= 0 ?  "0".repeat((prec + 2 - O.length)) : "");
 								}
 							} else if(prec === 0) O = O.charAt(0) + (alt ? "." : "");
-						} else if(prec > 0) O = O + "." + (prec >= 0 ? padstr["0"].substr(0,prec) : "");
+						} else if(prec > 0) O = O + "." + (prec >= 0 ? "0".repeat(prec) : "");
 						else if(alt) O = O + ".";
 						O = "0x" + O + "p" + (E>=0 ? "+" + E : E);
 						break;
@@ -566,9 +558,9 @@ function doit(t, args) {
 			/* width */
 			if(width > O.length) {
 				if(flags.indexOf("-") > -1) {
-					O = O + ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "");
+					O = O + ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "");
 				} else if(flags.indexOf("0") > -1 && O.length > 0 && isf) {
-					pad = ((width - O.length) >= 0 ? padstr[ "0"].substr(0,(width - O.length)) : "");
+					pad = ((width - O.length) >= 0 ?  "0".repeat((width - O.length)) : "");
 					if(O.charCodeAt(0) < 48) {
 						if(O.charAt(2).toLowerCase() == "x") O = O.substr(0,3) + pad + O.substring(3);
 						else O = O.substr(0,1) + pad + O.substring(1);
@@ -576,7 +568,7 @@ function doit(t, args) {
 					else if(O.charAt(1).toLowerCase() == "x") O = O.substr(0,2) + pad + O.substring(2);
 					else O = pad + O;
 				} else {
-					O = ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "") + O;
+					O = ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "") + O;
 				}
 			}
 			if(c < 96) O = O.toUpperCase();
diff --git a/printj.mjs b/printj.mjs
index decfc8c..19bd6fb 100644
--- a/printj.mjs
+++ b/printj.mjs
@@ -7,7 +7,7 @@
 
 var PRINTJ/*:PRINTJModule*/ = /*::(*/{}/*:: :any)*/;
 
-PRINTJ.version = '1.2.0';
+PRINTJ.version = '1.2.1';
 
 export const version = PRINTJ.version;
 
@@ -133,14 +133,6 @@ function tokenize(fmt/*:string*/)/*:ParsedFmt*/ {
 	return out;
 }
 
-//#define PAD_(x,c) (x >= 0 ? new Array(((x)|0) + 1).join((c)) : "")
-var padstr/*:{[s:string]:string}*/ = {
-	" ": "                                 ",
-	"0": "000000000000000000000000000000000",
-	"7": "777777777777777777777777777777777",
-	"f": "fffffffffffffffffffffffffffffffff"
-};
-
 var u_inspect/*:(o:any)=>string*/ = JSON.stringify;
 
 function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
@@ -190,7 +182,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 				/* only valid flag is "-" for left justification */
 				O = String(arg);
 				if( prec >= 0) O = O.substr(0,  prec);
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 			/* first char of string or convert */
@@ -205,7 +197,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 					case "string": O = /*::(*/arg/*:: :string)*/.charAt(0); break;
 					default: O = String(arg).charAt(0);
 				}
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 			/* int diDuUoOxXbB */
@@ -293,7 +285,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 				O = (arg) ? (alt ? "yes" : "true") : (alt ? "no" : "false");
 				if(c == /*Y*/ 89) O = O.toUpperCase();
 				if( prec >= 0) O = O.substr(0,  prec);
-				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? padstr["0"].substr(0, width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? padstr[" "].substr(0, width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
+				if( width > O.length || - width > O.length) { if(( flags.indexOf("-") == -1 ||  width < 0) &&  flags.indexOf("0") != -1) { pad = ( width - O.length >= 0 ? "0".repeat( width - O.length) : ""); O = pad + O; } else { pad = ( width - O.length >= 0 ? " ".repeat( width - O.length) : ""); O =  flags.indexOf("-") > -1 ? O + pad : pad + O; } }
 				break;
 
 		}
@@ -355,16 +347,16 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 				if(radix == 16 || radix == -16) {
 					O = (Vnum>>>0).toString(16);
 					Vnum = Math.floor((Vnum - (Vnum >>> 0)) / Math.pow(2,32));
-					O = (Vnum>>>0).toString(16) + (8 - O.length >= 0 ? padstr[ "0"].substr(0,8 - O.length) : "") + O;
-					O = (16 - O.length >= 0 ? padstr[ "f"].substr(0,16 - O.length) : "") + O;
+					O = (Vnum>>>0).toString(16) + (8 - O.length >= 0 ?  "0".repeat(8 - O.length) : "") + O;
+					O = (16 - O.length >= 0 ?  "f".repeat(16 - O.length) : "") + O;
 					if(radix == 16) O = O.toUpperCase();
 				} else if(radix == 8) {
 					O = (Vnum>>>0).toString(8);
-					O = (10 - O.length >= 0 ? padstr[ "0"].substr(0,10 - O.length) : "") + O;
+					O = (10 - O.length >= 0 ?  "0".repeat(10 - O.length) : "") + O;
 					Vnum = Math.floor((Vnum - ((Vnum >>> 0)&0x3FFFFFFF)) / Math.pow(2,30));
 					O = (Vnum>>>0).toString(8) + O.substr(O.length - 10);
 					O = O.substr(O.length - 20);
-					O = "1" + (21 - O.length >= 0 ? padstr[ "7"].substr(0,21 - O.length) : "") + O;
+					O = "1" + (21 - O.length >= 0 ?  "7".repeat(21 - O.length) : "") + O;
 				} else {
 					Vnum = (-Vnum) % 1e16;
 					var d1/*:Array<number>*/ = [1,8,4,4,6,7,4,4,0,7,3,7,0,9,5,5,1,6,1,6];
@@ -385,8 +377,8 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 			if(prec ===0 && O == "0" && !(radix == 8 && alt)) O = ""; /* bail out */
 			else {
 				if(O.length < prec + (O.substr(0,1) == "-" ? 1 : 0)) {
-					if(O.substr(0,1) != "-") O = (prec - O.length >= 0 ? padstr[ "0"].substr(0,prec - O.length) : "") + O;
-					else O = O.substr(0,1) + (prec + 1 - O.length >= 0 ? padstr[ "0"].substr(0,prec + 1 - O.length) : "") + O.substr(1);
+					if(O.substr(0,1) != "-") O = (prec - O.length >= 0 ?  "0".repeat(prec - O.length) : "") + O;
+					else O = O.substr(0,1) + (prec + 1 - O.length >= 0 ?  "0".repeat(prec + 1 - O.length) : "") + O.substr(1);
 				}
 
 				/* add prefix for # form */
@@ -407,10 +399,10 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 			if(width > 0) {
 				if(O.length < width) {
 					if(flags.indexOf("-") > -1) {
-						O = O + ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "");
+						O = O + ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "");
 					} else if(flags.indexOf("0") > -1 && prec < 0 && O.length > 0) {
-						if(prec > O.length) O = ((prec - O.length) >= 0 ? padstr[ "0"].substr(0,(prec - O.length)) : "") + O;
-						pad = ((width - O.length) >= 0 ? padstr[ (prec > 0 ? " " : "0")].substr(0,(width - O.length)) : "");
+						if(prec > O.length) O = ((prec - O.length) >= 0 ?  "0".repeat((prec - O.length)) : "") + O;
+						pad = ((width - O.length) >= 0 ?  (prec > 0 ? " " : "0").repeat((width - O.length)) : "");
 						if(O.charCodeAt(0) < 48) {
 							if(O.charAt(2).toLowerCase() == "x") O = O.substr(0,3) + pad + O.substring(3);
 							else O = O.substr(0,1) + pad + O.substring(1);
@@ -418,7 +410,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 						else if(O.charAt(1).toLowerCase() == "x") O = O.substr(0,2) + pad + O.substring(2);
 						else O = pad + O;
 					} else {
-						O = ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "") + O;
+						O = ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "") + O;
 					}
 				}
 			}
@@ -465,8 +457,8 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 						O = Vnum.toExponential(20);
 						E = +O.substr(O.indexOf("e")+1);
 						O = O.charAt(0) + O.substr(2,O.indexOf("e")-2);
-						O = O + (E - O.length + 1 >= 0 ? padstr[ "0"].substr(0,E - O.length + 1) : "");
-						if(alt || (prec > 0 && isnum !== 11)) O = O + "." + (prec >= 0 ? padstr[ "0"].substr(0,prec) : "");
+						O = O + (E - O.length + 1 >= 0 ?  "0".repeat(E - O.length + 1) : "");
+						if(alt || (prec > 0 && isnum !== 11)) O = O + "." + (prec >= 0 ?  "0".repeat(prec) : "");
 						break;
 
 					/* e/E exponential */
@@ -480,7 +472,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 
 					/* a/A hex */
 					case 4:
-						if(Vnum===0){O= "0x0"+((alt||prec>0)?"."+(prec >= 0 ? padstr["0"].substr(0,prec) : ""):"")+"p+0"; break;}
+						if(Vnum===0){O= "0x0"+((alt||prec>0)?"."+(prec >= 0 ? "0".repeat(prec) : ""):"")+"p+0"; break;}
 						O = Vnum.toString(16);
 						/* First char 0-9 */
 						var ac/*:number*/ = O.charCodeAt(0);
@@ -527,11 +519,11 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 							if(prec > 0) {
 								O = O.substr(0, prec + 2);
 								if(O.length < prec + 2) {
-									if(O.charCodeAt(0) < 48) O = O.charAt(0) + ((prec + 2 - O.length) >= 0 ? padstr[ "0"].substr(0,(prec + 2 - O.length)) : "") + O.substr(1);
-									else O += ((prec + 2 - O.length) >= 0 ? padstr[ "0"].substr(0,(prec + 2 - O.length)) : "");
+									if(O.charCodeAt(0) < 48) O = O.charAt(0) + ((prec + 2 - O.length) >= 0 ?  "0".repeat((prec + 2 - O.length)) : "") + O.substr(1);
+									else O += ((prec + 2 - O.length) >= 0 ?  "0".repeat((prec + 2 - O.length)) : "");
 								}
 							} else if(prec === 0) O = O.charAt(0) + (alt ? "." : "");
-						} else if(prec > 0) O = O + "." + (prec >= 0 ? padstr["0"].substr(0,prec) : "");
+						} else if(prec > 0) O = O + "." + (prec >= 0 ? "0".repeat(prec) : "");
 						else if(alt) O = O + ".";
 						O = "0x" + O + "p" + (E>=0 ? "+" + E : E);
 						break;
@@ -548,9 +540,9 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 			/* width */
 			if(width > O.length) {
 				if(flags.indexOf("-") > -1) {
-					O = O + ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "");
+					O = O + ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "");
 				} else if(flags.indexOf("0") > -1 && O.length > 0 && isf) {
-					pad = ((width - O.length) >= 0 ? padstr[ "0"].substr(0,(width - O.length)) : "");
+					pad = ((width - O.length) >= 0 ?  "0".repeat((width - O.length)) : "");
 					if(O.charCodeAt(0) < 48) {
 						if(O.charAt(2).toLowerCase() == "x") O = O.substr(0,3) + pad + O.substring(3);
 						else O = O.substr(0,1) + pad + O.substring(1);
@@ -558,7 +550,7 @@ function doit(t/*:ParsedFmt*/, args/*:Array<any>*/)/*:string*/ {
 					else if(O.charAt(1).toLowerCase() == "x") O = O.substr(0,2) + pad + O.substring(2);
 					else O = pad + O;
 				} else {
-					O = ((width - O.length) >= 0 ? padstr[ " "].substr(0,(width - O.length)) : "") + O;
+					O = ((width - O.length) >= 0 ?  " ".repeat((width - O.length)) : "") + O;
 				}
 			}
 			if(c < 96) O = O.toUpperCase();
diff --git a/shim.js b/shim.js
index e3d7840..4493b85 100644
--- a/shim.js
+++ b/shim.js
@@ -235,3 +235,42 @@ if (typeof ArrayBuffer !== 'undefined' && !ArrayBuffer.prototype.slice) {
     return target;
   };
 }
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat
+if (!String.prototype.repeat) {
+  String.prototype.repeat = function(count) {
+    'use strict';
+    if (this == null) {
+      throw new TypeError('can\'t convert ' + this + ' to object');
+    }
+    var str = '' + this;
+    count = +count;
+    if (count != count) {
+      count = 0;
+    }
+    if (count < 0) {
+      throw new RangeError('repeat count must be non-negative');
+    }
+    if (count == Infinity) {
+      throw new RangeError('repeat count must be less than infinity');
+    }
+    count = Math.floor(count);
+    if (str.length == 0 || count == 0) {
+      return '';
+    }
+    // Ensuring count is a 31-bit integer allows us to heavily optimize the
+    // main part. But anyway, most current (August 2014) browsers can't handle
+    // strings 1 << 28 chars or longer, so:
+    if (str.length * count >= 1 << 28) {
+      throw new RangeError('repeat count must not overflow maximum string size');
+    }
+    var maxCount = str.length * count;
+    count = Math.floor(Math.log(count) / Math.log(2));
+    while (count) {
+       str += str;
+       count--;
+    }
+    str += str.substring(0, maxCount - str.length);
+    return str;
+  };
+}
diff --git a/test.js b/test.js
index b073a51..ef30c84 100644
--- a/test.js
+++ b/test.js
@@ -190,4 +190,7 @@ describe('special cases', function() {
 		assert.equal(sprintf("|%*.*s|", 4,  0, "sheetjs"), "|    |");
 		assert.equal(sprintf("|%*.*s|", 4, -1, "sheetjs"), "|sheetjs|");
 	});
+	it('handles long strings', function() {
+		for(var i = 10; i <= 1000; i+= 10) assert.equal(sprintf("%" + i + "s", "abc").length, i);
+	});
 });
diff --git a/types/bin_printj.ts b/types/bin_printj.ts
index f5de475..c1c5d67 100644
--- a/types/bin_printj.ts
+++ b/types/bin_printj.ts
@@ -1,8 +1,8 @@
 /* printj.ts (C) 2016-present SheetJS -- http://sheetjs.com */
 /* vim: set ts=2 ft=typescript: */
-/*jshint node:true, evil:true */
+/// <reference types="node" />
 import X = require("printj");
-let argv = ["n:1","a","e:null","f:3.4", "b:true", "e:1+1"];
+const argv = ["n:1","a","e:null","f:3.4", "b:true", "e:1+1"];
 
 function help() {
 [
@@ -10,6 +10,7 @@ function help() {
 "",
 "Options:",
 "    -h, --help      output usage information",
+"    -d, --dump      print debug information about format string",
 "",
 "Arguments are treated as strings unless prefaced by a type indicator:",
 "    n:<integer>     call parseInt (ex. n:3 -> 3)",
@@ -32,22 +33,32 @@ return 0;
 }
 
 function parse_arg(arg: string): any {
-	let m: string = arg.substr(2), p: number = 0;
+	const m: string = arg.substr(2);
+	let p: number = 0;
 	if(arg.charCodeAt(1) === 58) switch((p = arg.charCodeAt(0))) {
 		case /*n*/ 110: return parseInt(m, 10);
 		case /*f*/ 102: return parseFloat(m);
 		case /*b*/  98: return !(m.toUpperCase() === "FALSE" || m === "0");
 		case /*j*/ 106: return JSON.parse(m);
+		case /*e*/ 101: return /*eval*/(m);
 		case /*s*/ 115: return m;
 	}
 	return arg;
 }
 
-let args: any[] = [];
+const args: any[] = [];
 let fmt = "", n = 0;
 for(let i = 2; i < argv.length; ++i) switch(argv[i]) {
-	case "--help": case "-h": break;
+	case "--help": case "-h": process.exit(help()); break;
+	case "--dump": case "-d": if(fmt.length===0) fmt = argv[++i]; process.exit(dump(fmt)); break;
 	default: if(n++ === 0) fmt = argv[i]; else args.push(parse_arg(argv[i]));
 }
 
 console.log(X.vsprintf(fmt, args));
+process.exit(0);
+
+function dump(fmt: string): number {
+	if(!fmt) { console.error("printj: missing format argument"); return 1; }
+	// X._tokenize(fmt).forEach(function(x){console.log(x);});
+	return 0;
+}
diff --git a/types/tsconfig.json b/types/tsconfig.json
index 7a65429..5c276fe 100644
--- a/types/tsconfig.json
+++ b/types/tsconfig.json
@@ -4,7 +4,7 @@
         "lib": [ "es5", "dom" ],
         "noImplicitAny": true,
         "noImplicitThis": true,
-        "strictNullChecks": false,
+        "strictNullChecks": true,
         "baseUrl": ".",
         "paths": { "printj": ["."] },
         "types": [],
diff --git a/types/tslint.json b/types/tslint.json
index d9401a9..a4589d3 100644
--- a/types/tslint.json
+++ b/types/tslint.json
@@ -1,11 +1,13 @@
 {
 	"extends": "dtslint/dtslint.json",
 	"rules": {
+		"no-implicit-dependencies": false,
 		"whitespace": false,
 		"no-sparse-arrays": false,
 		"only-arrow-functions": false,
 		"no-consecutive-blank-lines": false,
 		"prefer-conditional-expression": false,
+		"prefer-const": true,
 		"one-variable-per-declaration": false
 	}
 }