From 2e818b7beafe567a19447c81f9a033e32cc2022f Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Wed, 23 Mar 2016 00:11:16 +0000
Subject: Improve collapsing of elements when there are empty elements

Specifically, strip out empty nodes before attempting to collapse.
---
 NEWS                         |  4 ++++
 lib/html/simplify.js         | 36 +++++++++++++++++++++---------------
 tests/html/simplify.tests.js | 14 ++++++++++++++
 3 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/NEWS b/NEWS
index c10d83e..7375048 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,7 @@
+# 0.3.33
+
+* Improve collapsing of elements when there are empty elements.
+
 # 0.3.32
 
 * Allow bold and italic style mappings to be configured.
diff --git a/lib/html/simplify.js b/lib/html/simplify.js
index 5b65034..24a3447 100644
--- a/lib/html/simplify.js
+++ b/lib/html/simplify.js
@@ -1,33 +1,37 @@
 var ast = require("./ast");
 
 function simplify(node) {
-    return removeEmpty(simplifiers[node.type](node));
+    return collapse(removeEmpty(node));
 }
 
-var simplifiers = {
-    fragment: simplifyFragment,
-    element: simplifyElement,
+function collapse(node) {
+    return collapsers[node.type](node);
+}
+
+var collapsers = {
+    fragment: collapseFragment,
+    element: collapseElement,
     selfClosingElement: identity,
     text: identity,
     forceWrite: identity
 };
 
-function simplifyFragment(node) {
-    return ast.fragment(simplifyNodes(node.children));
+function collapseFragment(node) {
+    return ast.fragment(collapseNodes(node.children));
 }
 
-function simplifyElement(node) {
-    return ast.elementWithTag(node.tag, simplifyNodes(node.children));
+function collapseElement(node) {
+    return ast.elementWithTag(node.tag, collapseNodes(node.children));
 }
 
 function identity(value) {
     return value;
 }
 
-function simplifyNodes(nodes) {
+function collapseNodes(nodes) {
     var children = [];
     
-    nodes.map(simplify).forEach(function(child) {
+    nodes.map(collapse).forEach(function(child) {
         appendChild(children, child, children.push.bind(children));
     });
     return children;
@@ -58,15 +62,17 @@ var emptiers = {
 };
 
 function fragmentEmptier(fragment) {
-    return ast.fragment(fragment.children.filter(function(child) {
-        return !child.isEmpty;
-    }));
+    return ast.fragment(listEmptier(fragment.children));
 }
 
 function elementEmptier(element) {
-    return ast.elementWithTag(element.tag, element.children.filter(function(child) {
+    return ast.elementWithTag(element.tag, listEmptier(element.children));
+}
+
+function listEmptier(elements) {
+    return elements.map(removeEmpty).filter(function(child) {
         return !child.isEmpty;
-    }));
+    });
 }
 
 
diff --git a/tests/html/simplify.tests.js b/tests/html/simplify.tests.js
index 2a16ba4..db7beb4 100644
--- a/tests/html/simplify.tests.js
+++ b/tests/html/simplify.tests.js
@@ -78,4 +78,18 @@ describe("simplify", function() {
                 nonFreshElement("blockquote", {}, [nonFreshElement("p", {}, [text("there")])])])),
             fragment([nonFreshElement("blockquote", {}, [nonFreshElement("p", {}, [text("Hello"), text("there")])])]));
     });
+    
+    test("empty elements are removed before collapsing", function() {
+        var freshPath = htmlPaths.elements([
+            htmlPaths.element("p", {}, {fresh: true})]);
+        var nonFreshPath = htmlPaths.elements([
+            htmlPaths.element("p", {}, {fresh: false})]);
+        assert.deepEqual(
+            html.simplify(fragment([
+                pathToNode(nonFreshPath, [text("Hello")]),
+                pathToNode(freshPath, []),
+                pathToNode(nonFreshPath, [text(" there")])])),
+            fragment([
+                pathToNode(nonFreshPath, [text("Hello"), text(" there")])]));
+    });
 });
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