added generation function for generate pdf

src/app/services/file.service.ts

@@ -0,0 +1,31 @@
+import { Injectable } from '@angular/core';
+import {HttpResponse} from "@angular/common/http";
+
+@Injectable({
+  providedIn: 'root',
+})
+export class FileService {
+    getFilenameFromHttpResponse(httpResponse: HttpResponse<Blob>) {
+        const contentDispositionHeader = httpResponse.headers.get('Content-Disposition');
+        // console.log(contentDispositionHeader);
+        let result = contentDispositionHeader.split(';')[1].trim().split('=')[1];
+        // Removing the " from the after trim operation
+        result = result.replace(/"/g, '');
+        // Removing . from filename
+        // return result.replace(/./g, '_');
+
+        return result;
+    }
+
+    downloadBlob(data: HttpResponse<Blob>) {
+        const url = window.URL.createObjectURL(data.body);
+        const anchor = document.createElement('a');
+
+        anchor.download = this.getFilenameFromHttpResponse(data);
+        anchor.href = url;
+        anchor.click();
+        anchor.remove();
+
+        window.URL.revokeObjectURL(url);
+    }
+}