[documentation] documentation on how to compile dart to js for a non-web target with webdev build

[iapicca]

I want to compile dart to js for a non-web target (eg. fermyon/js, node)

I'm told it's possible with 2 possible approaches:

1. webdev build --no-release suggested here
2. dart compile js --server-mode suggested here with a 3rd party node_preamble

it would be nice to have some documentation on how to achieve this the 1. approach.

I admit that this is a skill issue rather than a dart issue
but maybe I'm not the only developer facing this and a minimal example would be great

here is a reproducible setup/example using node (repo)

node example

• set up node dependencies

npm init -y && \
npm install express && \
npm install --save-dev typescript @types/node @types/express ts-node-dev

• create the file tsconfig.json with the code below

{
    "compilerOptions": {
      "allowJs": true,
      "target": "ES6",
      "module": "commonjs",
      "strict": true,
      "esModuleInterop": true,
      "skipLibCheck": true,
      "outDir": "./dist",
      "rootDir": "./src"
    },
    "include": ["src"]
  }  

• create the file `src/greeting.js with the following code

export function greeting() {
    return "Hello from JS"
}

• create the file src/index.ts with the code below

import express, { Request, Response } from 'express';
import { greeting } from './greeting.js';

const app = express();
const port = 3000;

app.get('/', (req: Request, res: Response) => {
  res.send(greeting());
});

app.listen(port, () => {
  console.log(`Server is running on http://localhost:${port}`);
});

how can I create an equivalent

String greeting() => 'Hello from Dart';

import it and use it in index.ts?

notes

• packages from node_interop's family seem to me that are "replacing" node rather than actually "interop"
• stack overflow question

cc
@maks & @sigmundch from dart-lang/sdk#53884
@nex3 I've been told on Twitter that you have experience with this use case from sass

[nex3]

From the Sass end, we've built the cli_pkg package to encapsulate the logic for releasing a package to various platforms, including as a Node.js library. See the npm docs and the pkg.jsModuleMainLibrary documentation for details.

[bkonyi]

It sounds like this is an area we could do better documenting, but I think this might belong in the SDK issue tracker if we're going to be guiding users to use dart compile js. I'll look into moving this issue there.