Add fallback content types

2 files changed, 39 insertions, 6 deletions

diff --git a/lib/docx/content-types-reader.js b/lib/docx/content-types-reader.js
index a5f7ec0..fc95771 100644
--- a/lib/docx/content-types-reader.js
+++ b/lib/docx/content-types-reader.js
@@ -1,10 +1,17 @@
 exports.readContentTypesFromXml = readContentTypesFromXml;
-exports.defaultContentTypes = {
-    findContentType: function(path) {
-        return null;
-    }
+
+var fallbackContentTypes = {
+    "png": "png",
+    "gif": "gif",
+    "jpeg": "jpeg",
+    "jpg": "jpeg",
+    "tif": "tiff",
+    "tiff": "tiff",
+    "bmp": "bmp"
 };
 
+exports.defaultContentTypes = contentTypes({}, {});
+
 
 function readContentTypesFromXml(xml) {
     var extensionDefaults = {};
@@ -22,7 +29,10 @@ function readContentTypesFromXml(xml) {
             overrides[name] = child.attributes.ContentType;
         }
     });
-    
+    return contentTypes(overrides, extensionDefaults);
+}
+
+function contentTypes(overrides, extensionDefaults) {
     return {
         findContentType: function(path) {
             var overrideContentType = overrides[path];
@@ -31,8 +41,18 @@ function readContentTypesFromXml(xml) {
             } else {
                 var pathParts = path.split(".");
                 var extension = pathParts[pathParts.length - 1];
-                return extensionDefaults[extension];
+                if (extensionDefaults.hasOwnProperty(extension)) {
+                    return extensionDefaults[extension];
+                } else {
+                    var fallback = fallbackContentTypes[extension];
+                    if (fallback) {
+                        return "image/" + fallback;
+                    } else {
+                        return null;
+                    }
+                }
             }
         }
     };
+    
 }
diff --git a/tests/docx/content-types-reader.tests.js b/tests/docx/content-types-reader.tests.js
index 3b8c1d3..3390e43 100644
--- a/tests/docx/content-types-reader.tests.js
+++ b/tests/docx/content-types-reader.tests.js
@@ -24,4 +24,17 @@ describe('readContentTypesFromXml', function() {
         });
         assert.equal(contentTypes.findContentType("word/media/hat.png"), "image/hat");
     });
+    
+    test('fallback content types have common image types', function() {
+        var contentTypes = readContentTypesFromXml({
+            root: new XmlElement("content-types:Types", {}, [])
+        });
+        assert.equal(contentTypes.findContentType("word/media/hat.png"), "image/png");
+        assert.equal(contentTypes.findContentType("word/media/hat.gif"), "image/gif");
+        assert.equal(contentTypes.findContentType("word/media/hat.jpg"), "image/jpeg");
+        assert.equal(contentTypes.findContentType("word/media/hat.jpeg"), "image/jpeg");
+        assert.equal(contentTypes.findContentType("word/media/hat.bmp"), "image/bmp");
+        assert.equal(contentTypes.findContentType("word/media/hat.tif"), "image/tiff");
+        assert.equal(contentTypes.findContentType("word/media/hat.tiff"), "image/tiff");
+    });
 });