fixes title generation issues re: Service Worker and partials (GoogleChrome#2309)

* don't escape title

* use path title as fallback title, don't show undefined

* web.dev default title

* fix typo

Author: samthor

src/lib/sw.js

@@ -225,7 +225,7 @@ workboxRouting.registerRoute(
     const meta = partial.offline ? `<meta name="offline" value="true" />` : "";
     const output = layoutTemplate.replace(
       "%_CONTENT_REPLACE_%",
-      meta + `<title>${escape(partial.title)}</title>` + partial.raw,
+      meta + `<title>${partial.title || ""}</title>` + partial.raw,
     );
     const headers = new Headers();
     headers.append("Content-Type", "text/html");

src/site/_includes/components/Meta.js

@@ -109,7 +109,7 @@ module.exports = (locale, page, collections, renderData = {}) => {
 
   // prettier-ignore
   return html`
-    <title>${pageData.title || pageData.path.title}</title>
+    <title>${pageData.title || pageData.path.title || "web.dev"}</title>
     <meta name="description" content="${pageData.description || pageData.path.description}" />
 
     ${renderGoogleMeta()}

src/site/_includes/layout.njk

@@ -150,7 +150,7 @@
     <main>
       {% include 'partials/banner.njk' %}
       <div id="content">
-        {% Partial page, lang, title, offline %}{{ content | safe }}{% endPartial %}
+        {% Partial page, path, lang, title, offline %}{{ content | safe }}{% endPartial %}
       </div>
     </main>
     {% include 'partials/footer.njk' %}

src/site/_utils/build-partial.js

@@ -34,7 +34,7 @@ const writePartial = async (to, raw) => {
 module.exports = function buildPartial() {
   const work = [];
 
-  return function(content, page, lang, title, offline) {
+  return function(content, page, pathData, lang, title, offline) {
     if (!page.outputPath.endsWith("/index.html")) {
       return content; // unexpected output format
     }
@@ -46,7 +46,7 @@ module.exports = function buildPartial() {
     const partial = {
       raw: content,
       lang,
-      title,
+      title: title || (pathData && pathData.title) || "web.dev",
       offline: offline || undefined,
     };