Clean up torrent client API interface

api/torrent/src/IpcClient.ts

@@ -45,11 +45,22 @@ export abstract class IpcClient<M extends Microservice = Microservice> extends I
         return <ITorrent[]>response.data;
     }
 
+    /**
+     * Check if the torrent client has the given torrent
+     */
+    public async has(torrentId: string) {
+        let response = await this.request("has", torrentId);
+        if (response.error) {
+            console.error(response.error);
+            throw new Error("Failed to check if a torrent exists");
+        }
+        return <Boolean>response.data;
+    }
+
     /**
      * Get full details of each of the provided torrents
-     * @param torrentIds Array of torrent info hashes
      */
-    public async details(...torrentIds: string[]) {
+    public async details(torrentIds: string[] = []) {
         let response = await this.request("details", torrentIds);
         if (response.error) {
             console.error(response.error);