Zip API: append

JavaScript

jszip - npm

javascript - How to Zip files using jszip library - Stack Overflow

Stuk/jszip: Create, read and edit .zip files with Javascript @GitHub

A library for creating, reading and editing .zip files with JavaScript, with a lovely and simple API.

See https://stuk.github.io/jszip for all the documentation.

dual-licensed. You may use it under the MIT license or the GPLv3

5 M downloads / week

alternative lib, less features?

cthackers/adm-zip: A Javascript implementation of zip for nodejs. Allows user to create or extract zip files both in memory or to/from disk @GitHub

The library allows you to:

• decompress zip files directly to disk or in memory buffers
• compress files and store them to disk in .zip format or in compressed buffers
• update content of/add new/delete files from an existing .zip

adm-zip - npm

MIT, 3.1M downloads/week

ADM ZIP · cthackers/adm-zip Wiki

node.js - How to add my file to an existing zip-folder using node-js in lambda? - Stack Overflow

Python 

Python's zipfile: Manipulate Your ZIP Files Efficiently – Real Python