How to convert files to .RAR file node js - angularjs

Question

In my project I have a table of projects. For each project there is a column for downloading pdf file. Now I want to be able to download all files and to create a single .rar file. There is a code for downloading a single file:
routes.js
app.get('/api/download/archive/:filename', function(req,res){
res.download("public/uploads/"+req.params.filename, req.params.filename);
})
archive.js
$scope.downloadPdf = function(obj){
$http.get('api/download/archive/'+obj.Documentation)
.success(function(data){
window.open('api/download/archive/'+obj.Documentation)
});
}

Answer 1

Unfortunately, RAR is a closed-source software. So the only way to create an archive is to install the command-line utility called rar and then use rar a command in a child process to compress the files.
To install rar on Mac I had to run brew install homebrew/cask/rar. You can find the installation instructions for other platforms here.
After you install it you can make use of child_process like this:
const { exec } = require('child_process');
const { promisify } = require('util');
const fs = require('fs');
const path = require('path');
// Promisify `unlink` and `exec` functions as by default they accept callbacks
const unlinkAsync = promisify(fs.unlink);
const execAsync = promisify(exec);
(async () => {
// Generating a different name each time to avoid any possible collisions
const archiveFileName = `temp-archive-${(new Date()).getTime()}.rar`;
// The files that are going to be compressed.
const filePattern = `*.jpg`;
// Using a `rar` utility in a separate process
await execAsync(`rar a ${archiveFileName} ${filePattern}`);
// If no error thrown the archive has been created
console.log('Archive has been successfully created');
// Now we can allow downloading it
// Delete the archive when it's not needed anymore
// await unlinkAsync(path.join(__dirname, archiveFileName));
console.log('Deleted an archive');
})();
In order to run the example please put some .jpg files into the project directory.
PS: If you choose a different archive format (like .zip) you would be able to make use of something like archiver for example. That might allow you to create a zip stream and pipe it to response directly. So you would not need to create any files on a disk.
But that's a matter of a different question.

Answer 2

Try WinrarJs.
The project lets you Create a RAR file, Read a RAR file and Extract a RAR archive.
Here's the sample from GitHub:
/* Create a RAR file */
var winrar = new Winrar('/path/to/file/test.txt');
// add more files
winrar.addFile('/path/to/file/test2.txt');
// add multiple files
winrar.addFile(['/path/to/file/test3.txt', '/path/to/file/test4.txt']);
// set output file
winrar.setOutput('/path/to/output/output.rar');
// set options
winrar.setConfig({
password: 'testPassword',
comment: 'rar comment',
volumes: '10', // split volumes in Mega Byte
deleteAfter: false, // delete file after rar process completed
level: 0 // compression level 0 - 5
});
// archiving file
winrar.rar().then((result) => {
console.log(result);
}).catch((err) => {
console.log(err);
}

Answer 3

Unfortunately Nodejs dosn't native support Rar compression/decompression, i frustated with this too so i created a module called "super-winrar" making super easy deal with rar files in nodejs :)
check it out: https://github.com/KiyotakaAyanokojiDev/super-winrar
Exemple creating rar file "pdfs.rar" and appending all pdf files into:
const Rar = require('super-winrar');
const rar = new Rar('pdfs.rar');
rar.on('error', error => console.log(error.message));
rar.append({files: ['pdf1.pdf', 'pdf2.pdf', 'pdf3.pdf']}, async (err) => {
if (err) return console.log(err.message);
console.log('pdf1, pdf2 and pdf3 got successfully put into rar file!');
rar.close();
});