Enable reading `.node-version` (or similarly structured) file to read the node version

[justinedelson]

Expected Behaviour

It is frequently important to have the runtime node version match the version used locally and in CI (e.g. to run tests). Similarly to how the setup-node or asdf-vm/actions/install actions work in GitHub Actions, it should be possible for hedy to read the node version from a file so that the following are controlled in one place:

• Local node version (e.g. via asdf)
• GitHub Actions (e.g. via the setup-node or asdf-vm/actions/install action)
• Runtime version

Proposed Syntax

node-version-file CLI argument and nodeVersionFile package configuration should be able to contain a relative file path. If present and the file contains a parseable value, this should be used as the node version. If the value is a simple integer, that's the node version. If the value contains a two or three segment version (i.e. 20.1.2) then only the first segment is used.

Similar to the setup-node action, if both node-version-file and node-version are configured, node-version is used.

[tripodsan]

I think this can be solved through https://docs.npmjs.com/cli/v6/configuring-npm/package-json#engines

[justinedelson]

I think engines means something slightly different -- that is intended to represent a range of versions that can be used whereas .node-version (when used with a version manager), setup-node/node-version and node-version in hedy configuration say "this is the version to use"

[tripodsan]

but using package.json as node version would work:
https://github.com/actions/setup-node/blob/main/docs/advanced-usage.md#node-version-file

so you can keep the build version (engines) and the deploy version (wsk.node-version) close together in the same file.

[justinedelson]

Ah, I understand now. Yes, that provides some locality. And TBH if it was just a matter of GitHub Actions + hedy this wouldn't be necessary since you can extract the version set up by the setup-node action as an output and use it to generate a HLX_NODE_VERSION environment variable.

But this leaves local execution out. I clarified this in my original message.