Merge pull request #190 from brewern/render_nothing_when_empty

Add configuration for rendering nothing if the diff shows no changes were made.

README.md

@@ -188,6 +188,7 @@ The HTML output accepts a Javascript object with configuration. Possible options
   - `maxLineLengthHighlight`: only perform diff changes highlight if lines are smaller than this, default is `10000`
   - `templates`: object with previously compiled templates to replace parts of the html
   - `rawTemplates`: object with raw not compiled templates to replace parts of the html
+  - `renderNothingWhenEmpty`: render nothing if the diff shows no change in its comparison: `true` or `false`, default is `false`
   > For more information regarding the possible templates look into [src/templates](https://github.com/rtfpessoa/diff2html/tree/master/src/templates)
 
 ** Diff2HtmlUI Helper Options **

src/diff2html.js

@@ -19,7 +19,8 @@
     matching: 'none',
     matchWordsThreshold: 0.25,
     matchingMaxComparisons: 2500,
-    maxLineLengthHighlight: 10000
+    maxLineLengthHighlight: 10000,
+    renderNothingWhenEmpty: false
   };
 
   /*

src/line-by-line-printer.js

@@ -26,6 +26,8 @@
   }
 
   LineByLinePrinter.prototype.makeFileDiffHtml = function(file, diffs) {
+    if (this.config.renderNothingWhenEmpty && file.blocks && !file.blocks.length) return '';
+
     var fileDiffTemplate = hoganUtils.template(baseTemplatesPath, 'file-diff');
     var filePathTemplate = hoganUtils.template(genericTemplatesPath, 'file-path');
     var fileIconTemplate = hoganUtils.template(iconsBaseTemplatesPath, 'file');

test/line-by-line-tests.js

@@ -279,6 +279,23 @@ describe('LineByLinePrinter', function() {
         '    </div>\n' +
         '</div>';
 
+      assert.equal(expected, fileHtml);
+    });
+    it('should return empty when option renderNothingWhenEmpty is true and file blocks not present', function() {
+      var lineByLinePrinter = new LineByLinePrinter({
+        renderNothingWhenEmpty: true
+      });
+
+      var file = {
+        blocks: []
+      };
+
+      var diffs = '<span>Random Html</span>';
+
+      var fileHtml = lineByLinePrinter.makeFileDiffHtml(file, diffs);
+
+      var expected = '';
+
       assert.equal(expected, fileHtml);
     });
   });
@@ -399,7 +416,7 @@ describe('LineByLinePrinter', function() {
         isCombined: false
       }];
 
-      var lineByLinePrinter = new LineByLinePrinter();
+      var lineByLinePrinter = new LineByLinePrinter({ renderNothingWhenEmpty: false });
       var html = lineByLinePrinter.generateLineByLineJsonHtml(exampleJson);
       var expected =
         '<div class="d2h-wrapper">\n' +