Retain fragments when switching to different versions/platforms of the docs

Author: Nemo157

static/index.js

@@ -25,4 +25,7 @@ function copyTextHandler() {
 (function() {
     const clipboard = document.getElementById("clipboard");
     if (clipboard != null) clipboard.addEventListener("click", copyTextHandler);
+    for (const e of document.querySelectorAll('a[data-fragment="retain"]')) {
+        e.addEventListener('mouseover', () => e.hash = document.location.hash);
+    }
 })();

templates/macros.html

@@ -123,8 +123,10 @@
         {# NOTE: `/` is part of target if it exists (to avoid `target-direct//path`) #}
         {% if inner_path == "" %} {# /crate #}
             {%- set release_url = "/crate/" ~ name ~ "/" ~ release.version -%}
+            {%- set retain_fragment = false -%}
         {% else %}
             {%- set release_url = "/crate/" ~ name ~ "/" ~ release.version ~ "/target-redirect/" ~ target ~ inner_path -%}
+            {%- set retain_fragment = true -%}
         {% endif %}
         {# The release's name and version, `:name-:version` #}
         {%- set release_name = name ~ "-" ~ release.version -%}
@@ -150,6 +152,7 @@
                 href="{{ release_url | safe }}"
                 class="pure-menu-link{% if warning %} warn{% endif %}"
                 {% if warning %} title="{{ warning }}"{% endif %}
+                {% if retain_fragment %}data-fragment="retain"{% endif %}
             >
                 {% if warning %}
                     {{ "exclamation-triangle" | fas(fw=true) }}

templates/rustdoc/topbar.html

@@ -194,6 +194,7 @@
 
         <li class="pure-menu-item">
             <a href="{{ latest_path | safe }}" class="pure-menu-link warn"
+                data-fragment="retain"
                 title="{{ tooltip }}">
                 {{ "exclamation-triangle" | fas }}
                 <span class="title">{{ title }}</span>
@@ -222,7 +223,7 @@
                 {%- set target_url = "/crate/" ~ metadata.name ~ "/" ~ metadata.version ~ "/target-redirect/" ~ target ~ "/" ~ inner_path -%}
 
                 <li class="pure-menu-item">
-                    <a href="{{ target_url | safe }}" class="pure-menu-link">{{ target }}</a>
+                    <a href="{{ target_url | safe }}" class="pure-menu-link" data-fragment="retain">{{ target }}</a>
                 </li>
             {%- endfor -%}
         </ul>