Free Software for JavaScript
Chart.js
Chart.js is an easy way to include animated, interactive graphs on your website. Chart.js is a free and open source charting library for JavaScript that is simple, yet flexible. With Chart.js you can mix and match bar and line charts to provide a clear visual distinction between datasets and easily create most common chart types.
Mocha.js
A simple, flexible, and feature-rich JavaScript test framework running on Node.js and in the browser, making asynchronous testing simple and fun. With Mocha, you can run tests serially, allowing for flexible and accurate reporting, while mapping uncaught exceptions to the correct test cases.
Whitestorm.js
WhitestormJS is a free and open source framework that can be used to build 3D web applications using Three.js technology. WhitestormJS uses Three.js for rendering your scene and objects and Physi.js for simulating physics. Both those libraries are already included in the build and should work properly out-of-the-box. Developers use WhitestormJS to build interactive 3D applications for the web.
nest.land
A blockchain-based package registry for Deno. nest.land combines Deno with the Arweave Blockchain to create a decentralized package registry for Deno. With nest.land developers can publish immutable Deno packages that can never be deleted and easily used for any Deno-powered software project.
knex.js
Knex.js is a free and open-source JavaScript query builder for relational databases. The query builder supports Postgres, MSSQL, MySQL, MariaDB, SQLite3, Oracle, and Amazon Redshift and is designed for easy-of-use and portability. Knex.js can be used with both callbacks and promises and supports transactions and connection pooling while providing async flow control, a stream interface, fully featured query and schema builders.
Mandarine.TS
Mandarine.TS is a free and open-source minimalist, decorator-driven, MVC framework for Deno. Mandarine consists of four different core modules, Core, Security, Data & MVC which brings a compact, SOLID oriented solution for complex applications. All Mandarine projects are released under the MIT License and its growth is dependant on the members in the community.
Owncast
With Owncast you can host your own streams. Owncast is a free and open-source, self-hosted live video and web chat server for use with existing popular broadcasting software. Owncast includes a web interface to your video with built-in chat that is available once you start the server. The web interface was specifically built to be editable by anybody comfortable tweaking a web page. Allowing streamers to customize the experience for their audience.
Storybook
Storybook is an open source tool for developing UI components in isolation for React, Vue, Angular, and more. It makes building stunning UIs organized and efficient.
Video.js
Make your video player yours with the world's most popular open source HTML5 player framework. Video.js is a free and open source HTML5 & Flash video player that you can use for any web application. The framework is designed to o be a reliable and consistent base to build on top of. Video.js comes with a well-documented plugin architecture has your back if you are in need to extend the functionality of your video player.