Sending Zip file from server to client browser with Express and Archiver - node.js

Question

I am a beginner with Node and I am trying to figure out how to create a zip file at the server then send it to the client and then download the zip file to the user's browser. I am using the Express framework and I am using Archiver to actually do the zipping. My server code is the following which was taken from Dynamically create and stream zip to client
router.get('/image-dl', function (req,res){
res.writeHead(200, {
'Content-Type': 'application/zip',
'Content-disposition': 'attachment; filename=myFile.zip'
});
var zip = archiver('zip');
// Send the file to the page output.
zip.pipe(res);
// Create zip with some files. Two dynamic, one static. Put #2 in a sub folder.
zip.append('Some text to go in file 1.', { name: '1.txt' })
.append('Some text to go in file 2. I go in a folder!', { name: 'somefolder/2.txt' })
.finalize();
});
So its zipping two text files and returning the result. On the client side I am using the following function in a service to actually call that endpoint
downloadZip(){
const headers = new Headers({'Content-Type': 'application/json'});
const token = localStorage.getItem('token')
? '?token=' + localStorage.getItem('token')
: '';
return this.http.get(this.endPoint + '/job/image-dl' + token, {headers: headers})
.map((response: Response) => {
const result = response;
return result;
})
.catch((error: Response) => {
this.errorService.handleError(error.json());
return Observable.throw(error.json());
});
}
and then I have another function which calls downloadZip() and actually downloads the zip file to the user's local browser.
testfunc(){
this.jobService.downloadZip().subscribe(
(blah:any)=>{
var blob = new Blob([blah], {type: "application/zip"});
FileSaver.saveAs(blob, "helloworld.zip");
}
);
}
When testfunc() is called, a zip file is downloaded to the user's browser however when I try to unzip it it creates a zip.cpgz file which then turns back into a zip file when clicked in an infinite loop which indicates that some kind of corruption happened. Can anyone see where I went wrong here?