From b43cc1ae918da47dceea730ee75c7e3e4365e12f Mon Sep 17 00:00:00 2001
From: Nick Brewer <brewer.nick@gmail.com>
Date: Thu, 31 Jan 2019 17:58:48 -0600
Subject: [PATCH] Add configuration option to disable the render of templates.

No template would render if the diff shows no difference in its comparison.
---
 src/diff2html.js            |  3 ++-
 src/line-by-line-printer.js |  2 ++
 test/line-by-line-tests.js  | 19 ++++++++++++++++++-
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/diff2html.js b/src/diff2html.js
index 7931496..6d7dba2 100644
--- a/src/diff2html.js
+++ b/src/diff2html.js
@@ -19,7 +19,8 @@
     matching: 'none',
     matchWordsThreshold: 0.25,
     matchingMaxComparisons: 2500,
-    maxLineLengthHighlight: 10000
+    maxLineLengthHighlight: 10000,
+    renderNothingWhenEmpty: false,
   };
 
   /*
diff --git a/src/line-by-line-printer.js b/src/line-by-line-printer.js
index bdba538..8b41cc5 100644
--- a/src/line-by-line-printer.js
+++ b/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');
diff --git a/test/line-by-line-tests.js b/test/line-by-line-tests.js
index 767e959..69b6dab 100644
--- a/test/line-by-line-tests.js
+++ b/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' +