No fallar con valores vacíos

_includes/share.html

@@ -1,9 +1,9 @@
 {% capture url %}{{ site.url }}{{ include.url }}{% endcapture %}
 
 {% unless include.share.url == '%url' %}
-  {% assign url = url | cgi_escape %}
+  {% assign url = url | default: '' | cgi_escape %}
 {% endunless %}
-{% assign title = include.title | cgi_escape %}
+{% assign title = include.title | default: '' | cgi_escape %}
 {% assign description = include.description | default: '' | cgi_escape %}
 
 <a

_layouts/post.html

@@ -4,10 +4,10 @@ layout: default
 
 <article class="h-entry" itemscope itemtype="http://schema.org/Article">
   <header>
-    <h1 class="p-name" itemprop="name headline">{{ page.title | escape }}</h1>
+    <h1 class="p-name" itemprop="name headline">{{ page.title | default: '' | escape }}</h1>
 
     {%- if page.description -%}
-      <p class="lead p-summary" itemprop="description">{{ page.description | escape }}</p>
+      <p class="lead p-summary" itemprop="description">{{ page.description | default: '' | escape }}</p>
     {%- endif -%}
 
     {%- if page.image.path -%}
@@ -29,7 +29,7 @@ layout: default
         •
         <span itemprop="author" itemscope itemtype="http://schema.org/Person">
           <span class="p-author h-card" itemprop="name">
-            {{ author | escape }}
+            {{ author | default: '' | escape }}
           </span>
         </span>
       {%- endfor -%}