utils: add ipfs module

src/utils/ipfs.ts

@@ -0,0 +1,27 @@
+/** https://docs.ipfs.tech/how-to/address-ipfs-on-web/#path-gateway */
+const IPFS_PATH_REGEX = /^\/ipfs\/([^/]+)/;
+/** https://docs.ipfs.tech/how-to/address-ipfs-on-web/#subdomain-gateway */
+const IPFS_HOST_REGEX = /^([^/]+)\.ipfs\./;
+
+/** Get IPFS CID out of a path. */
+function cidFromPath(path: string) {
+  return path.match(IPFS_PATH_REGEX)?.[1];
+}
+
+/** Get IPFS CID out of a host. */
+function cidFromHost(host: string) {
+  return host.match(IPFS_HOST_REGEX)?.[1];
+}
+
+/** Get IPFS CID out of a URL. */
+function cidFromUrl({ protocol, hostname, pathname }: URL) {
+  switch (protocol) {
+    case 'ipfs:':
+      return hostname;
+    case 'http:':
+    case 'https:':
+      return cidFromPath(pathname) || cidFromHost(hostname);
+  }
+}
+
+export { cidFromUrl };