1 files changed, 16 insertions, 4 deletions
diff --git a/src/library.js b/src/library.js
index 995fa2ab..2faa40d7 100644
--- a/src/library.js
+++ b/src/library.js
@@ -1974,6 +1974,7 @@ LibraryManager.library = {
         var flagLeftAlign = false;
         var flagAlternative = false;
         var flagZeroPad = false;
+        var flagPadSign = false;
         flagsLoop: while (1) {
           switch (next) {
             case {{{ charCode('+') }}}:
@@ -1992,6 +1993,9 @@ LibraryManager.library = {
                 flagZeroPad = true;
                 break;
               }
+            case {{{ charCode(' ') }}}:
+              flagPadSign = true;
+              break;
             default:
               break flagsLoop;
           }
@@ -2158,8 +2162,12 @@ LibraryManager.library = {
             }
 
             // Add sign if needed
-            if (flagAlwaysSigned && currArg >= 0) {
-              prefix = '+' + prefix;
+            if (currArg >= 0) {
+              if (flagAlwaysSigned) {
+                prefix = '+' + prefix;
+              } else if (flagPadSign) {
+                prefix = ' ' + prefix;
+              }
             }
 
             // Move sign to prefix so we zero-pad after the sign
@@ -2250,8 +2258,12 @@ LibraryManager.library = {
               if (next == {{{ charCode('E') }}}) argText = argText.toUpperCase();
 
               // Add sign.
-              if (flagAlwaysSigned && currArg >= 0) {
-                argText = '+' + argText;
+              if (currArg >= 0) {
+                if (flagAlwaysSigned) {
+                  argText = '+' + argText;
+                } else if (flagPadSign) {
+                  argText = ' ' + argText;
+                }
               }
             }