s3-zip-stream.ts

import AWS from 'aws-sdk';
import cfg from '../config';
import archiver from 'archiver';
import {Archiver} from 'archiver';
const s3 = new AWS.S3({
  region: cfg.awsRegion,
  signatureVersion: 'v4'
});

export type ObjectKeyWithPath = {
  path: string;
  objectKey: string;
};
export function appendZipStreamEntry(archive:Archiver, entry:ObjectKeyWithPath) {
  const objectStream = s3.getObject({
    Key: entry.objectKey,
		Bucket: cfg.awsS3Bucket
  }).createReadStream();
  archive.append(objectStream, {name: entry.path});
}
export function createZipStream(entries:ObjectKeyWithPath[]):Archiver {
  const archive = archiver('zip', {
    zlib: {level: 9}
  });
	archive.on('error', (err) => {
		throw err;
  });
  function* addEntries() {
    for (let i = 0; i < entries.length; i++) {
      yield appendZipStreamEntry(archive, entries[0]);
    }
    archive.finalize();
  }
  const entryGenerator = addEntries();
  entryGenerator.next();
  archive.on('entry', () => {
    entryGenerator.next();
  });
  return archive;
}