My API returning application/octet-stream response which I am able to download in zip format. But I want to extract the zip into an actual file before downloading.

fetch('./api'). // its returnType: arraybuffer  
.then((result) => {
 const blob = new Blob([result.body], { type: "application/octet-stream" }); // converting to blob
  //--------
  // Here Before downloading the file I want to extract and download the actual file
  //--------
 saveAs(blob, fileName); // file-saver lib using to download
});