Hey, I am trying to get environment variables into my KotlinJS application, but it just refuses to w...

# javascript

[Hildebrandt Tobias]

Hey, I am trying to get environment variables into my KotlinJS application, but it just refuses to work.
I use Kotlin Multiplatform with the latest gradle and kotlin version.
The webpack version is v5 I think.
I referenced this gist https://gist.github.com/CameronProbert/85b7d60fa9572d93566f5c5ee62441e0
and this discussion
https://discuss.kotlinlang.org/t/kotlin-js-react-accessing-configuring-environment-variables/16906/6
In my webpack config I put

;(function(config) {
    const webpack = require("webpack");
    const environmentPlugin = new webpack.DefinePlugin({
        'process.env.TEST_VALUE': JSON.stringify(process.env.TESTVALUE),
        // TEST_VALUE: process.env.TESTVALUE,
    })
    console.log("TESTVALUE: " + process.env.TESTVALUE)
    console.log(environmentPlugin)
    config.plugins.push(environmentPlugin)
})(config);

(I also tried EnvironmentPlugin but get the error TEST_VALUE undefined)
In gradle I added

webpackTask { args.plusAssign(listOf("--env", "TESTVALUE=$testVariable")) }

In my kotlin code I then get process is not defined and I don't know where to go from here.

[Hildebrandt Tobias]

I didn't know that process was a node library.
So I added it via implementation(devNpm("process", "0.11.10"))
And added a wrapper with

@file:JsModule("process")
@file:JsNonModule

external val process: dynamic

I can see the process library in the node_modules in the browser, but
console.log(process) still gives me process is not defined

[turansky]

Do you use IR compiler?

[turansky]

Valid declaration for start

external val process: dynamic

[Hildebrandt Tobias]

Yes, I do use the IR compiler

[Hildebrandt Tobias]

I also tried

@file:JsModule("process/browser.js")

[turansky]

More elegant and strict:

external object process {
    object env {
        val TEST_VALUE: String
    }
}

[Hildebrandt Tobias]

Yeah, I tried to shrink it down to avoid errors.
Before I had

external interface Process {
    val env: EnvironmentVariables
}
external object EnvironmentVariables {
    val TEST_VALUE: String
}

[turansky]

You can start from unsafe variant:

val a = js("process.env.TEST_VALUE")

to check webpack configuration

[Hildebrandt Tobias]

I'll check again, but I also tried this I think.

[turansky]

I use compiler plugin for such declarations

[turansky]

You can find example example here

[turansky]

Configuration for DefinePlugin will be in generated folder webpack.config.d

[Hildebrandt Tobias]

Oh that's a nice hint. Thank you.
I tried the above and

val test = js("process.env.TEST_VALUE")
println(test)

gives `undefined`but there is no crash.

[turansky]

You need 2 things:
1. process.env.TEST_VALUE call in generated JS. Without intermediate variables
2. Valid DefinePlugin configuration - you can find it generated sources of compiler plugin

[Hildebrandt Tobias]

seskar gives me Configuration with name 'jsMainImplementation' not found.

[Hildebrandt Tobias]

My gradle JS config is

js("jsFrontend", IR)

and

val jsFrontendMain by getting { ... }

[Hildebrandt Tobias]

Okay

const environmentPlugin = new webpack.DefinePlugin({
        'process.env.TEST_VALUE': JSON.stringify("TESTTEST"),
        // TEST_VALUE: process.env.TESTVALUE,
    })

Works, I now have to get the env into the webpack and I'm fine.
Seskar also looks very good.
But I'll get back to it when I have more breathing room. Thank you

[Hildebrandt Tobias]

Okay slight backpaddel

val test = js("process.env.TEST_VALUE")
    println(test)

Works, but

@file:JsModule("process")
@file:JsNonModule
package common.environment

external object process {
    object env {
        val TEST_VALUE: String
    }
}

doesn't. But that is okay for now.

[turansky]

Annotations are fully redundant

[Hildebrandt Tobias]

Oh and they actively prevented it from working.
Now as a last step I need to get the variables from gradle into webpack.
Thank you

[Hildebrandt Tobias]

Okay for the afterworld here is a working example

Gradle

val testVariable = System.getenv("TEST_VARIABLE") ?: "default"
kotlin {
    js("jsFrontend", IR) {
        binaries.executable()
        browser {
            commonWebpackConfig(
                Action {
                    // In a split multiplatform project webpack fudges the
                    // output file name, so we have to set it manually.
                    outputFileName = "${rootProject.name}-jsFrontend-js-frontend.js"
                    cssSupport {
                        enabled.set(true)
                    }
                    export = false
                }
            )
            webpackTask { args.plusAssign(listOf("--env", "TESTVALUE=$testVariable")) }
            runTask { args.plusAssign(listOf("--env", "TESTVALUE=$testVariable")) }
        }
    }
    sourceSets {
        val jsFrontendMain by getting {
            dependencies {
                implementation(devNpm("process", "0.11.10"))
            }
        }
    }
}

webpack.config.js //this snipped must be the last to be added in the resulting generated config.js

module.exports = (env) => {
    const definePlugin = new webpack.DefinePlugin({
        'process.env.TEST_VALUE': JSON.stringify(env.TESTVALUE),
    })
    config.plugins.push(definePlugin)
    return config
}

Process.kt

external object process {
    object env {
        val TEST_VALUE: String
    }
}

Client.kt

val testtest = process.env.TEST_VALUE
    println(testtest)

Hope it helps.

[turansky]

plusAssign -> += ?

[Hildebrandt Tobias]

Tested it, also works yes