Support engines field when .nvmrc / .node-version are not present

[amitdahan]

Summary

Adds support for engines field in package.json so having the following is supported with fnm use and fnm install:

{
  "name": "my-thing",
  "engines": {
    "node": ">= 13.3.7 < 14.0.0"
  }
}

(Relies on #816 and #991)

Since this isn't directly equivalent to the "locked" nature of .nvmrc or .node-version, this feature will start as experimental, and behind an opt-in --resolve-engines:

[changeset-bot]

🦋 Changeset detected

Latest commit: 88bc36a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

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fnm	Minor

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[ljharb]

The engines field is a range, not a single version, and affects consumers - it’s not meant to be used for the developer’s node version.

If the feature only worked when the app is private: true, then at least that would avoid the risk of breaking consumers, but it’s still a conceptual mismatch to use a ranged field for a single version.

[Schniz]

lgtm overall. What do you think of my comments?

[kud]

That's really great. Is there any way to auto-detect this? My shell already starts fnm use when a config file is found.

[Schniz]

fnm env --use-on-cd works with this feature for auto detection

[Schniz]

If not, let us know

[amitdahan]

Yep, just add --resolve-engines:

(I'm using Zsh)

eval "$(fnm env --use-on-cd --resolve-engines)"

[kud]

Oh wow, indeed, simple!

Thank you guys!

[kud]

None works actually.

eval "$(fnm env --use-on-cd --resolve-engines)" > /dev/null 2>&1

in zsh.

[Schniz]

yeah seems like it's broken on use-on-cd, let's open an issue and fix it

[Schniz]

it failed when I tested on a docker container, yet worked on my machine: it's because I'm using --version-file-strategy=recursive. I wonder if this should just become the default now. cc @amitdahan

[gotounix]

I found it not work on Windows (PowerShell):

$env:FNM_MULTISHELL_PATH = "C:\Users\Max\AppData\Local\fnm_multishells\7196_1708612586200"
$env:FNM_VERSION_FILE_STRATEGY = "local"
$env:FNM_COREPACK_ENABLED = "false"
$env:FNM_RESOLVE_ENGINES = "true"
$env:FNM_DIR = "C:\Users\Max\AppData\Roaming\fnm"
$env:FNM_NODE_DIST_MIRROR = "https://nodejs.org/dist"
$env:FNM_ARCH = "x64"
$env:FNM_LOGLEVEL = "info"
E:\test [master ≡ +1 ~1 -0 !]> fnm use --resolve-engines
error: Can't find version in dotfiles. Please provide a version manually to the command.

@Schniz