The benefit of using Kotlin to generate JS binaries is that I can have a single language for all my source code, without having to master many different languages.

If the following goals can be achieved by this project, then I can use Kotlin Javascript multiplatform to build CLI (Node.js) apps and Browser based apps (that run in Chrome or electron):

• Use KT to write web apps that run in Node.js (CLI), Browser (Vanilla JS), and Browser (React).
• Be able to import JS deps (that have TS bindings) and use them (eg: lodash, Ink3, etc).
• Be able to debug KT code, after it has compiled to JS and is running Browser or Node.js.

Kotlin MP uses a gradle as its build system, and JB has created a gradle plugin "Kotlin/JS plugin" - org.jetbrains.kotlin.js (very similar to what they did for IDEA plugins) that actually orchestrates a few things:

• Kotlin/JS IR compiler that compiles KT code to IR code and then to JS
  • It is possible to use the LEGACY compiler, but that isn't recommended because Kotlin 1.4.x is all about the new IR compiler backend. Since I don't have any old code, I don't have to worry about the lack of binary compatibility (of generated JS) between the LEGACY and IR compilers.
• Yarn to handle npm deps
  • Dukat to handle TS type defs for npm deps
• Webpack to build the artifacts
• Allows for selecting browser or Node.js execution environments
  • Configure Node.js package.json settings
  • Configure browser settings
• Allows for run configurations to be declared
• Allows for test configurations to be declared
• And more.

Here are the official docs on configuring the kotlin { js(IR) { nodejs { ... } } } portion of the build.gradle.kts file.

The things in ... are:

• binaries.executable() - This causes the compiler to emit executable .js files.
• dependencies { ... } - The things that go in here are:
  • The Kotlin/JS standard library is always imported, so there's nothing to add here for it.
  • You have to import the kotlin.test library if you have tests.
  • You can also import the kotlinx-nodejs experimental library if you want direct access to Node.js APIs.
  • npm deps can be added here with this syntax.
    • Eg of npm dep: implementation(npm("react", "> 14.0.0 <=16.9.0"))
    • Eg of npm devDep: implementation(devNpm(...))

• Node.js debugging fails!
  • More info