add newEntries event

src/listener-rss.ts

@@ -17,6 +17,7 @@ export class ListenerRss extends EventEmitter {
   // private fields
   parser: Parser;
   loopRunning: boolean = false;
+  lastEntriesLinks: string[] = [];
 
   /**
    * @brief constructor
@@ -66,7 +67,22 @@ export class ListenerRss extends EventEmitter {
 
     const fun: () => void = () => {
       this.fetchRSS()
-        .then((obj: { [key: string]: any }) => this.emit("update", obj))
+        .then((obj: { [key: string]: any }) => {
+          this.emit("update", obj);
+          const updatedEntriesLinks = obj.items.map(
+            (item: { link: string }) => item.link
+          );
+
+          const newEntries = obj.items.filter(
+            (item: { link: string }) =>
+              !this.lastEntriesLinks.includes(item.link)
+          );
+
+          if (this.lastEntriesLinks.length !== 0 && newEntries.length !== 0) {
+            this.emit("newEntries", newEntries);
+          }
+          this.lastEntriesLinks = updatedEntriesLinks;
+        })
         .catch((err) => this.emit("error", err));
     };