while.rb in ruby2js-3.0.0

- old
+ new

@@ -7,9 +7,22 @@
 
     handle :while do |condition, block|
       begin
         next_token, @next_token = @next_token, :continue
 
+        # handle while loops that assign a variable
+        while condition.type == :begin and condition.children.length == 1
+          condition = condition.children.first
+        end
+
+        if condition.type == :lvasgn
+          var = condition.children[0]
+          unless @vars[var]
+            put "#{es2015 ? 'let' : 'var'} #{var}#@sep" 
+            @vars[var] = true
+          end
+        end
+
         put 'while ('; parse condition; puts ') {'; scope block; sput '}'
       ensure
         @next_token = next_token
       end
     end