There are 3 repositories under scala-js topic.
A better build tool for Java, Scala and Kotlin: 3-6x faster than Maven or Gradle, less fiddling with plugins, and more easily explorable in your IDE
Scala macros for compile-time generation of safe and ultra-fast JSON codecs + circe booster
Simple & Efficient data access for Scala and Scala.js
Describe HTTP endpoints in Scala and derive clients, servers, and documentation
Elm-inspired Scala UI library.
https://disneystreaming.github.io/smithy4s/
property based testing library for Scala
Using the latest technology in the Scala ecosystem, Boilerplay is a reactive web application built on Play Framework, ScalaJS, Silhouette, Sangria/GraphQL, and PostgreSQL. It provides a good starting point for whatever you want to build.
Cross-platform compilation support for sbt.
Typescript to Scala.js converter
Next generation user interface and application development in Scala and Scala.js for web, mobile, and desktop.
experimental CPS transformer for dotty
Scala FP configuration library with a focus on runtime clarity
RTree2D is a 2D immutable R-tree for ultra-fast nearest and intersection queries in plane and spherical coordinates
Scala configuration library supporting HOCON for Scala, Java, Scala.js, and Scala Native
Scala types for your library to represent HTML tags, attributes, properties and CSS styles
Create React apps in Scala with no build configuration.
Compile-time JSON marshaling and abstraction for Scala, Scala Native and Scala.js
Fully working client + server, dev + prod setup for Scala.js development, showcasing a bunch of Laminar & Scala.js patterns.
Clean room implementation of the LSP protocol in Scala, published for JVM, JS, and Native platforms
A Typesafe-logging (and slf4j) compatible logging library based on macros for Scala/JVM, Scala.js, and Scala Native
Implementation of java locale for scala.js
Demos for ScalablyTyped
Json/Protobuf convertors for ScalaPB use circe