Request: Add a --default option to install

[jcollum]

It'd be nice if I could combine

✗ nvm install 8 && nvm alias default 8

into:

✗ nvm install --default 8

That's all 👍

[ljharb]

Seems like a reasonable request - we could also add --alias=foo (and have --default be a shortcut for --alias=default) to cover the generic case.

[gitburd]

@ljharb Some work was done on this issue here: #1929 but the issue was not closed. Is this something that still needs to be done?

[ljharb]

@gitburd yes! it looks like #1929 (comment) still needs to be addressed.

If you'd like to rebase and update it, rather than opening up another PR, could you comment (here, or there) with a link to your branch, and I'll sync it with the PR?

[gitburd]

@ljharb Great! working on that now.

[gitburd]

@ljharb Here is my branch: https://github.com/gitburd/nvm/tree/add_default_alias_option
When I run this locally it only makes the alias in the alias=* cases if the version I am installing is already installed. Otherwise no alias is made.

[ljharb]

@gitburd I'm a bit confused; you're saying that the --alias option is currently not working when installing a version?

(note that the test I requested on that PR still doesn't exist; namely that nvm install --default --alias=blah errors out prior to installing)

I've updated the PR with your rebased changes, and also added the runtime error when both are provided (or when --alias or --default are provided more than once).