Handle embedding a style map into a document that already has one

2 files changed, 42 insertions, 6 deletions

diff --git a/lib/docx/style-map.js b/lib/docx/style-map.js
index 76f6903..04597a2 100644
--- a/lib/docx/style-map.js
+++ b/lib/docx/style-map.js
@@ -1,3 +1,5 @@
+var _ = require("underscore");
+
 var promises = require("../promises");
 var officeXml = require("./office-xml-reader");
 var xml = require("../xml");
@@ -6,6 +8,7 @@ exports.writeStyleMap = writeStyleMap;
 exports.readStyleMap = readStyleMap;
 
 
+var schema = "http://schemas.zwobble.org/mammoth/style-map";
 var styleMapPath = "mammoth/style-map";
 
 function writeStyleMap(docxFile, styleMap) {
@@ -18,14 +21,25 @@ function updateRelationships(docxFile) {
     var relationshipsUri = "http://schemas.openxmlformats.org/package/2006/relationships";
     return officeXml.readXmlFromZipFile(docxFile, path)
         .then(function(relationshipsDocument) {
-            var relationships = relationshipsDocument.root;
-            relationships.children.push(xml.element("{" + relationshipsUri + "}Relationship", {
-                "Id": "rMammothStyleMap",
-                "Type": "http://schemas.zwobble.org/mammoth/style-map",
+            var relationshipsContainer = relationshipsDocument.root;
+            var relationships = relationshipsContainer.children;
+            var relationshipId = "rMammothStyleMap";
+            var attributes = {
+                "Id": relationshipId,
+                "Type": schema,
                 "Target": "/" + styleMapPath
-            }));
+            };
+            
+            var existingRelationship = _.find(relationships, function(relationship) {
+                return relationship.attributes.Id === relationshipId;
+            });
+            if (existingRelationship) {
+                existingRelationship.attributes = attributes;
+            } else {
+                relationships.push(xml.element("{" + relationshipsUri + "}Relationship", attributes));
+            }
             var namespaces = {"": relationshipsUri};
-            return docxFile.write(path, xml.writeString(relationships, namespaces));
+            return docxFile.write(path, xml.writeString(relationshipsContainer, namespaces));
         });
     
 }
diff --git a/tests/docx/style-map.tests.js b/tests/docx/style-map.tests.js
index f1ac68d..fcf22ab 100644
--- a/tests/docx/style-map.tests.js
+++ b/tests/docx/style-map.tests.js
@@ -42,6 +42,28 @@ describe("style-map", function() {
             });
         });
     });
+    
+    test('re-embedding style map replaces original', function() {
+        var zip = normalDocx();
+        
+        var expectedRelationshipsXml = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>' +
+            '<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">' +
+            '<Relationship Id="rId3" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/settings" Target="settings.xml"/>' +
+            '<Relationship Id="rMammothStyleMap" Type="http://schemas.zwobble.org/mammoth/style-map" Target="/mammoth/style-map"/>' +
+            '</Relationships>';
+        
+        return styleMap.writeStyleMap(zip, "p => h1").then(function() {
+            return styleMap.writeStyleMap(zip, "p => h2");
+        }).then(function() {
+            return zip.read("word/_rels/document.xml.rels", "utf8").then(function(contents) {
+                assert.equal(contents, expectedRelationshipsXml);
+            });
+        }).then(function() {
+            return styleMap.readStyleMap(zip).then(function(contents) {
+                assert.equal(contents, "p => h2");
+            });
+        });
+    });
 });
 
 function normalDocx() {