[RRFC] Add `type` to `npm init`

[MylesBorins]

Motivation ("The Why")

The type field is used by many folks to be explicit about the how Node.js interprets the .js extension. It would be great if we could set this field by default, likely to commonjs and give folks the ability to overwrite the default with module (or any other future module type)

Example

{
  "type": commonjs"
}

How

Current Behaviour

Currently this is the default output of npm init --yes

{
  "name": "$FOLDERNAME",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "$USERNAME <$EMAIL>",
  "license": "ISC"
}

Desired Behaviour

{
  "name": "$FOLDERNAME",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "$USERNAME <$EMAIL>",
  "license": "ISC",
  "type": "commonjs"
}

References

https://nodejs.org/dist/latest-v14.x/docs/api/packages.html#packages_type

[thescientist13]

Just wanted to share there has been some initial discussion happening here if that is worth carrying over to this RFC - #75

[ljharb]

I’m not convinced this is actually helpful. In practice, tutorials have blindly recommended using type:module, and users who follow this advice invariably run into hours of debugging confusion until they realize either to remove it, or, until they learn all the caveats involved.

This is worsened because most ecosystem tooling is not yet able to handle type:module fully. There hopefully will be a time in the medium term where this is addressed, and perhaps the confusion factor would be addressed by that as well, but at the moment my experience helping newcomers tells me that the best thing for now is to avoid type:module (unless one is an expert).

Adding type:commonjs seems like it’d be fine, but if that includes a prompt, then it will be very difficult to concisely convey all the caveats and nuances of the choice, and users are highly likely to find themselves in the same boat i mentioned above.

[darcyclarke]

Just following up here, the general consensus seems to be to leave the base template of npm init alone & allow for the ecosystem to define templates/standards beyond those defaults (ex. create-pkg/npm init pkg is going to be a standard/default template that's defined by the Node Package Maintenance WG alongside some other tooling - ref. pkgjs/create-pkg#9)

Here's some references to our last few meeting notes:

• https://github.com/npm/rfcs/blob/latest/meetings/2021-03-17.md
• https://github.com/npm/rfcs/blob/latest/meetings/2021-04-14.md
• https://github.com/npm/rfcs/blob/latest/meetings/2021-04-07.md

Going to close based on the above

[jeffschwartz]

How about:
npm init -y --type-module

[wesbos]

I understand not wanting to change defaults, but could we at least get the ability to set init-type=module in our .npmrc file like we do with version, user, email and license? Seems there is no way to set the default to esm.