Support ESM for exporting server `--options`

It would be great if ESM projects could export const options when using the --options flag.

Like this:

export default async (fastify, opts) => {
  // ...
}

export const options = {
  maxParamLength: 200,
}

For now, this seems to work:

async function server(fastify, opts) {
  // ...
}

server.options = {
  maxParamLength: 200,
}

export default server

Not the end of the world, but I did spin my wheels for a bit thinking export const options would just work, since ESM is supported otherwise.

[laozhu]

I need this feature too, I want to use http2 feature by passing options in app.ts coding in ESM.

[nooreldeensalah]

@jstayton So I’ve initially tested this behavior on TypeScript, and it worked, this was the reason I’ve commented.

But indeed, testing it on JavaScript, it doesn’t work.

I think it works on TypeScript because it eventually gets compiled to commonjs (Attempting to check the script type when using TypeScript in util.js at line 69 returns commonjs). Which is not the case when using ESM in JavaScript (it returns module).

So, the reason this doesn’t work on ESM, is because the function used to load the file (line 85 in start.js) loads only the default export.

https://github.com/fastify/fastify-cli/blob/dd476a793a637da367d278a5041395ef1b909949/util.js#L72-L74

@mcollina Please re-open this issue