Deno development with Kotlin

Kotlin Deno example

🦕Deno development with Kotlin.

Features

• Deno completion: convert lib.deno.d.ts to Kotlin declarations

How it work?

• Compile kotlin into Javascript with nodejs target
• Append stub for Deno for compiled JS code like following.

// ========stub for Deno=======
import Kotlin from "https://jspm.dev/kotlin@1.4.0"

const module = {
    exports: {}
};

function require(moduleName) {
    if (moduleName === 'kotlin') {
        return Kotlin
    } else {
        return {};
    }
}

// ====== compiled JS code from Kotlin======

(function (_, Kotlin) {
   // ...
}(module.exports, require('kotlin')));

export default module.exports;

• Build the project

$ ./gradlew deno

• Run the code with Deno. Please add --no-check for Deno run to disable kotlin module check.

$ deno run --no-check build/deno/kotlin-deno-example.js

How to invoke Deno stdlib?

• Declare “external fun” for Kotlin in src/main/kotlin/deno/lib.std.kt
• Add imports in “buildSrc/src/scripts/deps.js”

Import other npm packages or Deno modules

• Use dukat to generate Kotlin declarations from xxx.d.ts or maintain lib.xxx.kt manually
• import Deno modules in deps.js
• import npm packages in deps.js by https://jspm.dev/xxx@version

Use Kotlinx Coroutines library

• add dependency in build.gradle.kts

implementation("org.jetbrains.kotlinx", "kotlinx-coroutines-core", "1.3.9")

• Add kotlinx-coroutines-core import in templates.js

import Kotlin from "https://jspm.dev/kotlin@1.4.0"
import KotlinxCoroutinesCore from "https://jspm.dev/kotlinx-coroutines-core@1.3.9"

//......

function require(moduleName) {
  if (moduleName === 'kotlin') {
    return Kotlin
  } else if (moduleName === 'kotlinx-coroutines-core') {
    return KotlinxCoroutinesCore;
  } else {
    return {};
  }
}

Kotlin/JS IR compiler

As of Kotlin 1.4.0, the Kotlin/JS IR compiler has Alpha stability level. With Kotlin/JS IR compiler support, and and compiled JS code is more clean.

Use cases

• Kotlin Deno App
• Kotlin as library: TypeScript to invoke JavaScript code compiled by Kotlin

Dev Tips

• Enables continuous build: re-execute tasks when task file inputs change

$ ./gradlew -t deno

• deno run --watch flags to watch file changes. Deno 1.4.0+ required

$ deno run --unstable --watch --allow-read --no-check build/deno/kotlin-deno-example.js

References

• Deno: https://deno.land/
• Kotlin: https://kotlinlang.org/
• lib.deno.d.ts: https://github.com/denoland/deno/releases/latest/download/lib.deno.d.ts
• dukat: Converter of TypeScript definition files to Kotlin declarations https://github.com/Kotlin/dukat
• jspm: provides a module CDN allowing any package from npm to be directly loaded in the browser and other JS environments https://jspm.org/

Download Details:

Author: linux-china

Source Code: https://github.com/linux-china/kotlin-deno-example

#deno #nodejs #node #javascript #kotlin