diff --git a/lib/output.js b/lib/output.js
index 85003290..54707f05 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -95,7 +95,7 @@ function OutputStream(options) {
             might_need_space = false;
         }
         if (might_need_semicolon) {
-            if (";{}".indexOf(ch) < 0 && !/[;]$/.test(OUTPUT)) {
+            if (";}".indexOf(ch) < 0 && !/[;]$/.test(OUTPUT)) {
                 OUTPUT += ";";
                 current_col++;
                 current_pos++;
@@ -672,6 +672,8 @@ function OutputStream(options) {
     });
     DEFPRINT(AST_UnaryPrefix, function(self, output){
         output.print(self.operator);
+        if (is_alphanumeric_char(self.operator.charAt(0)))
+            output.space();
         self.expression.print(output);
     });
     DEFPRINT(AST_UnaryPostfix, function(self, output){