From 3976fa34e97d653e7841970abde949ee094a29ed Mon Sep 17 00:00:00 2001
From: Radhi Fadlillah <m.radhi.f@gmail.com>
Date: Fri, 3 Apr 2020 09:38:34 +0700
Subject: [PATCH] Don't use data-old- prefix if old img attr not exists

---
 Readability.js                          | 28 +++++++++++--------------
 test/test-pages/citylab-1/expected.html |  2 +-
 2 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/Readability.js b/Readability.js
index 22c4bd5..7f4e3b0 100644
--- a/Readability.js
+++ b/Readability.js
@@ -1390,27 +1390,23 @@ Readability.prototype = {
         }
 
         var newImg = tmp.getElementsByTagName("img")[0];
-        var newImgSrc = newImg.getAttribute("src");
-        var newImgSrcset = newImg.getAttribute("srcset");
-        var prevImgSrc = prevImg.getAttribute("src");
-        var prevImgSrcset = prevImg.getAttribute("srcset");
-
-        if (prevImgSrc && prevImgSrc !== newImgSrc) {
-          newImg.setAttribute("data-old-src", prevImgSrc);
-        }
-
-        if (prevImgSrcset && prevImgSrcset !== newImgSrcset) {
-          newImg.setAttribute("data-old-srcset", prevImgSrcset);
-        }
-
         for (var i = 0; i < prevImg.attributes.length; i++) {
           var attr = prevImg.attributes[i];
-          if (attr.name == "src" || attr.name == "srcset" || newImg.hasAttribute(attr.name)) {
+          if (attr.value === "") {
             continue;
           }
 
-          if (/\.(jpg|jpeg|png|webp)/i.test(attr.value)) {
-            newImg.setAttribute(attr.name, attr.value);
+          if (attr.name === "src" || attr.name === "srcset" || /\.(jpg|jpeg|png|webp)/i.test(attr.value)) {
+            if (newImg.getAttribute(attr.name) === attr.value) {
+              continue;
+            }
+
+            var attrName = attr.name;
+            if (newImg.hasAttribute(attrName)) {
+                attrName = "data-old-" + attrName;
+            }
+
+            newImg.setAttribute(attrName, attr.value);
           }
         }
 
diff --git a/test/test-pages/citylab-1/expected.html b/test/test-pages/citylab-1/expected.html
index 4b32807..ac11141 100644
--- a/test/test-pages/citylab-1/expected.html
+++ b/test/test-pages/citylab-1/expected.html
@@ -12,7 +12,7 @@
             <meta itemprop="width" content="300" />
             <meta itemprop="url" content="https://cdn.citylab.com/media/img/citylab/2019/04/mr1/300.jpg?mod=1556645448" />
             <picture>
-                <source srcset="https://cdn.citylab.com/media/img/citylab/2019/04/mr1/300.jpg?mod=1556645448" media="(max-width: 575px)" /><img src="https://cdn.citylab.com/media/img/citylab/2019/04/mr1/300.jpg?mod=1556645448" alt="" data-old-srcset="https://cdn.citylab.com/media/img/citylab/2019/04/mr1/300.jpg?mod=1556645448" /></picture>
+                <source srcset="https://cdn.citylab.com/media/img/citylab/2019/04/mr1/300.jpg?mod=1556645448" media="(max-width: 575px)" /><img src="https://cdn.citylab.com/media/img/citylab/2019/04/mr1/300.jpg?mod=1556645448" alt="" srcset="https://cdn.citylab.com/media/img/citylab/2019/04/mr1/300.jpg?mod=1556645448" /></picture>
             <figcaption>
                 <span itemprop="caption">The Moulin Rouge cabaret in Paris</span> <span itemprop="creator">Benoit Tessier/Reuters</span>
             </figcaption>