flatpickr is a lightweight and powerful datetime picker.
Lean, UX-driven, and extensible, yet it doesn’t depend on any libraries. There’s minimal UI but many themes. Rich, exposed APIs and event system make it suitable for any environment.
This “lean” philosophy translates to less size and better performance, with a bonus of not having to load 8 libraries for a calendar.

BotMan is a framework agnostic PHP library that is designed to simplify the task of developing innovative bots for multiple messaging platforms, including Slack, Telegram, Microsoft Bot Framework, Nexmo, HipChat, Facebook Messenger and WeChat.

Neural Models of Syntax.

A TensorFlow toolkit for deep learning powered natural language understanding (NLU).

Styletron is a universal CSS-in-JS engine built from the ground up for high-performance.

Slate is a completely customizable framework for building rich text editors.

Slate lets you build rich, intuitive editors like those in Medium, Dropbox Paper or Canvas—which are becoming table stakes for applications on the web—without your codebase getting mired in complexity.

Machine Learning in Python

Simple and efficient tools for data mining and data analysis
Accessible to everybody, and reusable in various contexts
Built on NumPy, SciPy, and matplotlib
Open source, commercially usable - BSD license

Automatic and enhanced Google Analytics tracking for common user interactions on the web.

Element, a Vue 2.0 based component library for developers, designers and product managers, with a set of design resources.

RAW is an open web tool to create custom vector-based visualizations on top of the amazing d3.js library.

Primarily conceived as a tool for designers and vis geeks, RAW aims at providing a missing link between spreadsheet applications (e.g. Microsoft Excel, Apple Numbers, Google Docs, OpenRefine, …) and vector graphics editors (e.g. Adobe Illustrator, Inkscape, …).

RAW works with tabular data (e.g. spreadhseets and comma-separated values) as well as with copied-and-pasted texts from other applications (e.g. Microsoft Excel, TextWrangler, TextEdit, …). Based on the SVG format, visualizations can be easily edited with vector graphics applications for further refinements, or directly embedded into web pages.

Knowing the need of working with sensitive information, the data uploaded to RAW is processed only by the web browser: no server-side operations or storages are performed and no one will see, touch or copy your data!

Intern is a complete test system for JavaScript designed to help you write and run consistent, high-quality test cases for your JavaScript libraries and applications. It can be used to test any JavaScript code. It can even be used to test non-JavaScript Web and mobile apps, and to run tests written for other test systems.

A JavaScript framework for building data-driven React applications.
Never again communicate with your data store using an imperative API. Simply declare your data requirements using GraphQL and let Relay figure out how and when to fetch your data.
Queries live next to the views that rely on them, so you can easily reason about your app. Relay aggregates queries into efficient network requests to fetch only what you need.
Relay lets you mutate data on the client and server using GraphQL mutations, and offers automatic data consistency, optimistic updates, and error handling.

A library to generate PDFs in client-side JavaScript.

meSing.js is a JavaScript singing synthesis library that uses the Web Audio API's DSP capabilities in conjunction with the meSpeak.js speech synthesis library to provide a vocal synthesizer for the web.

Passport is authentication middleware for Node.js. Extremely flexible and modular, Passport can be unobtrusively dropped in to any Express-based web application. A comprehensive set of strategies support authentication using a username and password, Facebook, Twitter, and more.

Experimenting with window.onerror, trying to make JavaScript debugging easy.
What does it do?

Provides JavaScript error details in a readable format. You can log these errors remotely by enabling remoteLogging. After enabling, logerr will send a post request to the desired action/url with exception details along with custom parameters (if provided using additionalParams).

Redux is a predictable state container for JavaScript apps.

It helps you write applications that behave consistently, run in different environments (client, server, and native), and are easy to test. On top of that, it provides a great developer experience, such as live code editing combined with a time traveling debugger.

You can use Redux together with React, or with any other view library.

The Vanilla Javascript Repository. A searchable repository of dependency-free JavaScript libraries. Over 100 projects and growing.

A compact, cross-browser solution for using the JavaScript Notifications API

nlp_compromise does NLP in the browser. It's a handy, and not overly-fancy tool for understanding, changing, and playing with english. We've also got a modest, though ambitious plugin ecosystem.

Vue.js is a library for building interactive web interfaces. It provides data-reactive components with a simple and flexible API. Core features include:

Dead simple, unobtrusive reactivity using plain JavaScript objects.
Component-oriented development style with tooling support
Lean and extensible core
Flexible transition effect system
Fast without the need for complex optimization