Kotlin Firefox Extension build files https://medium.com/@Cypressious/your-second-firefox-extension-in-kotlin-bafd91d87c41

build.gradle

buildscript {
    ext.kotlin_version = '1.1.60'

    repositories {
        mavenCentral()
    }
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

version '1.0-SNAPSHOT'

allprojects {
    apply plugin: 'kotlin2js'
    apply plugin: 'kotlin-dce-js'

    repositories {
        mavenCentral()
    }

    dependencies {
        compile "org.jetbrains.kotlin:kotlin-stdlib-js:$kotlin_version"
    }

    compileKotlin2Js {
        kotlinOptions.sourceMap = true
        kotlinOptions.sourceMapEmbedSources = "always"
    }
}

settings.gradle

rootProject.name = 'kt-beastify'

include ':popup', ':content_script'