BurntSushi · August 14, 2019 11:46 · Aug 14, 2019
diff --git a/rustdoc-condensed.js b/rustdoc-condensed.js
@@ -0,0 +1,69 @@
+(function() {
+  // This function forces rustdoc to collapse documentation for all items,
+  // except for the methods defined in an impl block and the primary type's
+  // declaration. This is the most natural view IMO, since it provides the
+  // primary type along with an easy to scan overview of available methods.
+  //
+  // rustdoc does seemingly have user settings that purport to make this the
+  // default, but I could never cause them to work in a reliably consistent
+  // way. This is especially useful when writing documents, where you commonly
+  // want to refresh and look at the docs for the specific item you're working
+  // on. This mini-script will automatically scroll to and expand the currently
+  // selected method.
+  //
+  // I used the tridactyl Firefox extension to bind this script to `,z` with
+  // the following in my tridactylrc:
+  //
+  //     bind ,z composite jsb tri.native.run('cat path/to/rustdoc-condensed.js') | js -p eval(JS_ARG.content)
+
+  // get the currently selected doc item from URL's hash fragment
+  // e.g., in `struct.BStr.html#method.words`, this returns `method.words`.
+  function getPageId() {
+    var id = document.location.href.split("#")[1];
+    if (id) {
+      return id.split("?")[0].split("&")[0];
+    }
+    return null;
+  }
+
+  // collapse everything, with an extra click in case things are partially
+  // collapased already
+  const toggleAll = document.getElementById('toggle-all-docs');
+  if (toggleAll.className.indexOf('will-expand') > -1) {
+    toggleAll.click();
+  }
+  toggleAll.click();
+
+  // re-expand primary impls
+  const impls = document.getElementsByClassName('impl');
+  for (let i = 0; i < impls.length; i++) {
+    // but don't expand every impl, just the ones on this type
+    if (!/^impl(-\d+)?$/.test(impls[i].id)) {
+      continue;
+    }
+
+    const toggles = impls[i].getElementsByClassName('collapse-toggle');
+    for (let j = 0; j < toggles.length; j++) {
+      // If it's already expanded, then let it be. In newer versions of
+      // rustdoc, collapsing everything doesn't collapse the methods, so we
+      // don't need to do anything.
+      if (toggles[j].innerText == '[−]') {
+        continue;
+      }
+      toggles[j].click();
+    }
+  }
+
+  // expand type declaration docs
+  const main = document.getElementById('main');
+  const wrapper = document.getElementsByClassName('toggle-wrapper')[0];
+  wrapper.getElementsByTagName('a')[0].click();
+
+  // re-expand specific method declaration, and scroll to it
+  const pageId = getPageId();
+  if (pageId !== null) {
+    const method = document.getElementById(pageId);
+    method.getElementsByClassName('collapse-toggle')[0].click();
+    method.scrollIntoView();
+  }
+})()