Support aliases like LTS

[damccorm]

Right now, we're thinking it makes sense to support lts, latest, current, and LTS version names (e.g. dubinium)

[wesleytodd]

nodejs/package-maintenance#236

For reference, this is the alias list we are working out.

[JimiC]

@damccorm Do you mind if I give this a try to provide a PR?

[damccorm]

@JimiC that would be great! One thing to note is that we would like to make this completely automated (e.g. it shouldn't rely on hardcoding dubinium to 10.16).

I've done a small bit of digging here, here are some things that might be helpful (apologies if you already know any/all of this):

• http://nodejs.org/dist/ is the endpoint we hit right now. It has options for the latest versions of most of these packages.
• https://nodejs.org/dist/index.json in particular has a lot of useful info. Note in particular the lts fields.

[panva]

this may be useful as a reference for using the dist json file.

[JimiC]

@damccorm Great!
I had a look at the code and how you are fetching the node version and have an idea on how to tackle this issue. Before I start coding I'll present you my course of actions, in order for everyone to agree on it.

[ljharb]

You may also want to reference how https://github.com/nvm-sh/nvm parses that very tab file to support its LTS aliases.

[JimiC]

After a lot of thought and searching the docs of popular CI services (Azure Pipelines, AppVeyor, TravisCI, GitLab CI/CD, CircleCi) I come to the conclusion that the following should be supported:

# shorthand of the latest version of node
- node:
    alias:
        - ' '
        - current (?)
        - latest  (?)

# shorthand of node version 4
- argon:
    alias:
        - Argon

# shorthand of node version 6
- boron:
    alias:
        - Boron

# shorthand of node version 8
- carbon:
    alias:
        - Carbon

# shorthand of node version 10
- dubnium:
    alias:
        - Dubnium

# shorthand of node version 12
- erbium (?):
    alias:
        - Erbium

Those with a question mark are cases that I like to discuss with you.

• node is used as a shorthand in TravisCI and ' ' in AppVeyor. Should we also support those or are we going with our own shorthand like latest?
• Erbium is pending and can't be yet automated. I'm just mentioning it here as a placeholder.

From my POV lts/* should not be a choice, since the GitHub (Azure Pipelines) matrix.node-version property actually executes an iteration of the values specified, passing a single value of the version each time to create an instance.
lts/* resolves to multiple node versions that can't be interpreted into firing up multiple instances.

Similarly lts=dubnium should not be a choice either, simply specifying dubnium should suffice.

I'm not sure if lts should be a choice either. Which node version should lts point to?

[damccorm]

This generally looks great. A couple thoughts.

I think the idea of lts is that its the current lts. So right now, it would resolve to 10.x, but soon will resolve to 12.x. So lts and current are actually interchangeable here, while latest could resolve to a minor version (e.g. 13.x eventually). As long as we doc what we're doing there I think we'll be fine, the call from our product team based on customer conversations was supporting all 3 of these. I'd stick with these rather than go with a different placeholder, I think its a little more explicit this way.

Agreed on using dubinium instead of lts=dubinium.

Agreed on holding off on Erbium for now.

[JimiC]

One more clarification. According to https://nodejs.org/en/

• lts -> 10.x
• current -> 12.x which should also be resolved for shorthands ' ', node and latest

Correct?

Note: https://nodejs.org/en/about/releases/