Avoid prototype pollution when reading styles

1 files changed, 19 insertions, 8 deletions

diff --git a/lib/docx/styles-reader.js b/lib/docx/styles-reader.js
index 28c809b..276a668 100644
--- a/lib/docx/styles-reader.js
+++ b/lib/docx/styles-reader.js
@@ -27,16 +27,27 @@ function readStylesXml(root) {
     var tableStyles = {};
     var numberingStyles = {};
 
-    var styles = {
-        "paragraph": paragraphStyles,
-        "character": characterStyles,
-        "table": tableStyles,
-        "numbering": numberingStyles
-    };
-
     root.getElementsByTagName("w:style").forEach(function(styleElement) {
         var style = readStyleElement(styleElement);
-        var styleSet = styles[style.type];
+        var styleSet;
+
+        switch (style.type) {
+        case "paragraph":
+            styleSet = paragraphStyles;
+            break;
+
+        case "character":
+            styleSet = characterStyles;
+            break;
+
+        case "table":
+            styleSet = tableStyles;
+            break;
+
+        case "numbering":
+            styleSet = numberingStyles;
+            break;
+        }
 
         // Per 17.7.4.17 style (Style Definition) of ECMA-376 4th edition Part 1:
         //