Move URL abbreviation to its own util file

src/utils/UrlUtils.js

@@ -0,0 +1,49 @@
+/*
+Copyright 2019 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import url from "url";
+
+/**
+ * If a url has no path component, etc. abbreviate it to just the hostname
+ *
+ * @param {string} u The url to be abbreviated
+ * @returns {string} The abbreviated url
+ */
+export function abbreviateUrl(u) {
+    if (!u) return '';
+
+    const parsedUrl = url.parse(u);
+    // if it's something we can't parse as a url then just return it
+    if (!parsedUrl) return u;
+
+    if (parsedUrl.path === '/') {
+        // we ignore query / hash parts: these aren't relevant for IS server URLs
+        return parsedUrl.host;
+    }
+
+    return u;
+}
+
+export function unabbreviateUrl(u) {
+    if (!u) return '';
+
+    let longUrl = u;
+    if (!u.startsWith('https://')) longUrl = 'https://' + u;
+    const parsed = url.parse(longUrl);
+    if (parsed.hostname === null) return u;
+
+    return longUrl;
+}