1 files changed, 88 insertions, 0 deletions
diff --git a/browser/components/newtab/lib/ShortURL.sys.mjs b/browser/components/newtab/lib/ShortURL.sys.mjs
new file mode 100644
index 0000000000..6ee34c20dd
--- /dev/null
+++ b/browser/components/newtab/lib/ShortURL.sys.mjs
@@ -0,0 +1,88 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// We use importESModule here instead of static import so that
+// the Karma test environment won't choke on this module. This
+// is because the Karma test environment already stubs out
+// XPCOMUtils, and overrides importESModule to be a no-op (which
+// can't be done for a static import statement).
+
+// eslint-disable-next-line mozilla/use-static-import
+const { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+
+const lazy = {};
+
+XPCOMUtils.defineLazyServiceGetter(
+  lazy,
+  "IDNService",
+  "@mozilla.org/network/idn-service;1",
+  "nsIIDNService"
+);
+
+/**
+ * Properly convert internationalized domain names.
+ * @param {string} host Domain hostname.
+ * @returns {string} Hostname suitable to be displayed.
+ */
+function handleIDNHost(hostname) {
+  try {
+    return lazy.IDNService.convertToDisplayIDN(hostname, {});
+  } catch (e) {
+    // If something goes wrong (e.g. host is an IP address) just fail back
+    // to the full domain.
+    return hostname;
+  }
+}
+
+/**
+ * Get the effective top level domain of a host.
+ * @param {string} host The host to be analyzed.
+ * @return {str} The suffix or empty string if there's no suffix.
+ */
+export function getETLD(host) {
+  try {
+    return Services.eTLD.getPublicSuffixFromHost(host);
+  } catch (err) {
+    return "";
+  }
+}
+
+/**
+ * shortURL - Creates a short version of a link's url, used for display purposes
+ *            e.g. {url: http://www.foosite.com}  =>  "foosite"
+ *
+ * @param  {obj} link A link object
+ *         {str} link.url (required)- The url of the link
+ * @return {str}   A short url
+ */
+export function shortURL({ url }) {
+  if (!url) {
+    return "";
+  }
+
+  // Make sure we have a valid / parseable url
+  let parsed;
+  try {
+    parsed = new URL(url);
+  } catch (ex) {
+    // Not entirely sure what we have, but just give it back
+    return url;
+  }
+
+  // Clean up the url (lowercase hostname via URL and remove www.)
+  const hostname = parsed.hostname.replace(/^www\./i, "");
+
+  // Remove the eTLD (e.g., com, net) and the preceding period from the hostname
+  const eTLD = getETLD(hostname);
+  const eTLDExtra = eTLD.length ? -(eTLD.length + 1) : Infinity;
+
+  // Ideally get the short eTLD-less host but fall back to longer url parts
+  return (
+    handleIDNHost(hostname.slice(0, eTLDExtra) || hostname) ||
+    parsed.pathname ||
+    parsed.href
+  );
+}