support any semver value for install or use

[tjwebb]

Being able to, for example, use n to support automatic compatibility with any engines.node version in a package.json would be amazing. e.g.

$ n 0.10.x
$ n ">=0.10.0 <= 0.10.28"

Would be more convincing for programmatic-type usage, i.e. with n-api or similar:

var n = require('n-api');
n.use(pkg.engines.node, 'index.js');

[ghost]

I am going to assume that you would want n to install the latest of the wildcard version similar to the way npm installs from package.json? If so, I would like to give this a shot.

[bitdivine]

+1. This is exactly what I had in mind. Happy to help if needed.

[bitdivine]

Thoughts on how this might be used in practice, especially on the context of package.json:
Note: On the command line, wherever one can use, say "latest" as the version of node, one might use "engine":

n use engine ./server.js

Note: I know of no way of making npm use a specific version of node apart from putting that node at the front of the path. That one can do, with PATH="$(dirname "$(bin 5.0.0)"):$PATH" npm install. We might make this easy:

n with <version> npm install

or, shorter but less general:

n npm <version> install

Here are implementations to play with:

• fork: https://github.com/bitdivine/n
• code: bitdivine@215c100

[bitdivine]

Note: The sketch implementation uses the node modules semver and n-api. Of those, semver is what npm uses for its semantic versioning, so if npm is installed on a machine, so is semver. It doesn't add a new dependency and using the same code to do the comparison ensures that we always get the same answers. However n-api is not included in n or npm, so that dependency should probably be eliminated. The shell functions in n itself should be able to provide the n-api. ;-)

Note: Installing a new version with n engine will require a different logic from the one in the sketch. semantic_version() looks for a compatible version amongst all the installed versions. This needs another function that finds a compatible version among all versions that exist.

[shadowspawn]

This issue has not had any activity in over six months. It isn't likely to get acted on due to this report.

Feel free to open a new issue if it comes up again, with new information and renewed interest.

Thank you for your contributions.