Kotlin 1.4-M1 Typescript Definitions and React

Okay, so I am experimenting with the Kotlin 1.4-M1 pre-release, and am fully aware that it is beta. However, on reading that it can generate .d.ts files I was so excited I started a very small Hello World example. But no matter what I try I can’t get it to work in a React Typescript project. The modules are undefined, or something else is not found.

I tried nodejs() target, browser() target, tried different module systems. Everytime I get a nice .d.ts file like this:

declare namespace greeter_test_web {
    type Nullable<T> = T | null | undefined
    class Greeter {
        constructor(from: string)
        readonly from: string;
        greet(to: string): string

and a JS file that looks like:

(function (root, factory) {
  if (typeof define === 'function' && define.amd)
    define(['exports'], factory);
  else if (typeof exports === 'object')
    root['greeter-test-web'] = factory(typeof this['greeter-test-web'] === 'undefined' ? {} : this['greeter-test-web']);
}(this, function (_) {
  'use strict';
  function Greeter(from) {
      this._from = from;
  Greeter.prototype._get_from_ = function () {
    return this._from;
  Greeter.prototype.greet = function (to) {
    return '' + 'Hello ' + to + ' from ' + this._from + '!!';
  Greeter.$metadata$ = {
    simpleName: 'Greeter',
    kind: 'class',
    interfaces: []
  Object.defineProperty(Greeter.prototype, 'from', {
    get: Greeter.prototype._get_from_
  _.Greeter = Greeter;
  return _;

I create a React page like follows:

import React from 'react';
import './App.scss';

import "greeter-test-web";

const App : React.FunctionComponent = () => {
  const greeter = new greeter_test_web.Greeter("Kotlin/JS")
  return <h1>{ greeter.greet("world")}</h1>

export default App;

Please note that WebStorm autocompletes everything here in the tsx file.
But the result is everytime: “greeter_test_web” is not defined.

Does anyone have any pointers in how to get this simple example up and running?


I got it working! With type hinting.
It is a CommonJS module ofcourse…I don’t really like mixing in CommonJS in frontend projects like this.

import React from 'react';
import './App.scss';

const greeter_test_web = require("greeter-test-web"); // NOTE: don't rename te const to something else or type hinting doesn't work.

const App : React.FunctionComponent = () => {
  const greeter = new greeter_test_web.Greeter("Kotlin/JS");

  return <h1>{ greeter.greet("World") }</h1>

export default App;