Continued work on the send dialog

web/src/app/utils.js

@@ -22,10 +22,28 @@ export const shortUrl = (url) => url.replaceAll(/https?:\/\//g, "");
 export const expandUrl = (url) => [`https://${url}`, `http://${url}`];
 export const expandSecureUrl = (url) => `https://${url}`;
 
+export const splitTopicUrl = (url) => {
+    if (!validTopicUrl(url)) {
+        throw new Error("Invalid topic URL");
+    }
+    const parts = url.split("/");
+    if (parts.length < 2) {
+        throw new Error("Invalid topic URL");
+    }
+    return {
+        baseUrl: parts.slice(0, parts.length-1).join("/"),
+        topic: parts[parts.length-1]
+    };
+};
+
 export const validUrl = (url) => {
     return url.match(/^https?:\/\//);
 }
 
+export const validTopicUrl = (url) => {
+    return url.match(/^https?:\/\/.+\/.*[^/]/); // At least one other slash
+}
+
 export const validTopic = (topic) => {
     if (disallowedTopic(topic)) {
         return false;
@@ -115,6 +133,13 @@ export const shuffle = (arr) => {
     return arr;
 }
 
+export const splitNoEmpty = (s, delimiter) => {
+    return s
+        .split(delimiter)
+        .map(x => x.trim())
+        .filter(x => x !== "");
+}
+
 /** Non-cryptographic hash function, see https://stackoverflow.com/a/8831937/1440785 */
 export const hashCode = async (s) => {
     let hash = 0;