Marked is

1. built for speed.*
2. a low-level markdown compiler for parsing markdown without caching or blocking for long periods of time.**
3. light-weight while implementing all markdown features from the supported flavors & specifications.***
4. available as a command line interface (CLI) and running in client- or server-side JavaScript projects.

Most things that you can do manually in the browser can be done using Puppeteer! Here are a few examples to get you started:

Generate screenshots and PDFs of pages.
Crawl a SPA (Single-Page Application) and generate pre-rendered content (i.e. "SSR" (Server-Side Rendering)).
Automate form submission, UI testing, keyboard input, etc.
Create an up-to-date, automated testing environment. Run your tests directly in the latest version of Chrome using the latest JavaScript and browser features.
Capture a timeline trace of your site to help diagnose performance issues.
Test Chrome Extensions.

Simple yet flexible JavaScript charting for designers & developers

JavaScript UI library and framework for speeding up web development
JS Framework for cross-platform web Apps development
102 UI widgets and feature-rich CSS / HTML5 JavaScript controls

Evergreen is a React UI Framework for building ambitious products on the web. Made by Segment in San Francisco, CA.

Base Web is a foundation for initiating, evolving, and unifying web products.

Base Web offers a robust suite of components out of the box. These include complex, ready-to-use components such as Datepicker and low-level composable primitives, such as Layer.
For an overview of everything that we offer, check out the component gallery.

Positioning tooltips and popovers is difficult. Popper is here to help! Popper is the de facto standard to position tooltips and popovers in modern web applications.

Fully responsive. Scales with its container.
Separate settings per breakpoint
Uses CSS3 when available. Fully functional when not.
Swipe enabled. Or disabled, if you prefer.
Desktop mouse dragging
Infinite looping.
Fully accessible with arrow key navigation
Add, remove, filter & unfilter slides
Autoplay, dots, arrows, callbacks, etc...

D3.js is a JavaScript library for manipulating documents based on data. D3 helps you bring data to life using HTML, SVG, and CSS. D3’s emphasis on web standards gives you the full capabilities of modern browsers without tying yourself to a proprietary framework, combining powerful visualization components and a data-driven approach to DOM manipulation.

Build faster websites with less client-side JavaScript

Bien qu'Express soit le framework NodeJS archi dominant, Fastify propose une alternative moderne tout en restant un framework dit "de bas niveau", permettant aux développeurs de composer leurs applications avec les librairies de leurs choix.

Holory.fr

Tarteaucitron.js, un script pour gérer les cookies sur votre site en respectant les directives du RGPD et de la CNIL.

A React.js based library for creating sleek presentations using JSX syntax that gives you the ability to live demo your code.

A JavaScript library for efficient data fetching.