Remove trailing slashes when on pages.

Fixes CodeYourFuture#121

See commentary in CodeYourFuture#254 (comment)

docusaurus.config.js

@@ -13,14 +13,22 @@ module.exports = {
         docs: {
           sidebarPath: require.resolve("./sidebars.js"),
           editUrl: "https://github.com/CodeYourFuture/Syllabus-V2/edit/master/",
-          routeBasePath: "/", // Set this value to '/'.
+          routeBasePath: "/",
         },
         theme: {
           customCss: require.resolve("./src/css/custom.css"),
         },
       },
     ],
   ],
+  scripts: [
+    // See comments in static/js/fix-location.js
+    {
+      src: "/js/fix-location.js",
+      async: false,
+      defer: false
+    }
+  ],
   themeConfig: {
     googleAnalytics: {
       trackingID: "UA-159979458-2",

static/js/fix-location.js

@@ -0,0 +1,8 @@
+// Work around https://github.com/CodeYourFuture/syllabus/issues/121 by stripping trailing slashes from paths.
+//
+// See https://github.com/CodeYourFuture/syllabus/issues/121 and https://github.com/CodeYourFuture/syllabus/pull/254 and https://github.com/facebook/docusaurus/issues/2394 and https://github.com/facebook/docusaurus/issues/3372 for more context.
+
+// This workaround was borrowed from https://github.com/facebook/docusaurus/issues/2394#issuecomment-630638096
+if (window && window.location && window.location.pathname.endsWith('/') && window.location.pathname !== '/') {
+  window.history.replaceState('', '', window.location.pathname.substr(0, window.location.pathname.length - 1))
+}