Export VERSION information

[pgcalixto]

This is an attempt to resolve #747 and #799.

Closes #800.

I've read the contribution guide, but I do not know it there is anything to update in the documentation regarding the exports.

[jsf-clabot]

All committers have signed the CLA.

[pgcalixto]

@networkimprov it was needed to read the version from package.json (src/luxon.js, line 1).

I tried running without it first, but got error messages telling me to install plugin-json.

[GillesDebunne]

This seems fair.
Is it an 'official' way of exporting the VERSION? Can anyone reference some major libs that do it this way?

[pgcalixto]

@GillesDebunne, I retrieved the version from package.json because I've used this procedure to retrieve the package's name and version in some projects I worked in (both little personal projects and some bigger closed source projects for companies).
Also, this procedure of using require("package.json") to obtain the package's information seems to be present in a lot of code on GitHub: https://github.com/search?q=%22require(%27package.json%27)%22&type=Code

I tried to identify some major libs that also do this, but I had little success. I inspected code from some libs as lodash, moment, axios, request, chalk, fs-extra, etc.
While some of them do not export the version, the ones that do seem to do it manually.

• lodash/lodash@1b6c282
• moment/moment@19f4b11
  • https://github.com/moment/moment/blob/develop/tasks/bump_version.js#L9-L23
    Moment has a task for bumping the version export, but it seems to be run manually by the maintainers. From what I inspected, this bump_version task is not associated with any automated script.

We could think of a way to the same procedure as Moment's: first we would manually write the version export (1.25.0), and for the future releases, we run a task to bump it when.
While this loses some of the automation compared to the way I did, it still seems to work fine, as long as the bump_version task is always run when creating new releases.

I will try to look for more examples on how to do this and bring some references.

[pgcalixto]

How is the version bumped on Luxon (such as the commit below)? Is it manual?

345b1cd

[GillesDebunne]

Indeed, updating the version from package.json as part of a release script seems appropriate (scripts/tag already reads it).

[pgcalixto]

I quite didn't get your suggestion, @GillesDebunne. How do you think we should proceed?

[networkimprov]

Vue includes a version in its package.json: vuejs/vue@ec78fc8b which is visible at runtime as Vue.version

EDIT: I'm not familiar with its build process, but found this: https://github.com/vuejs/vue-next/pull/254/commits

[pgcalixto]

Thank you for the reference, @networkimprov!
Both Vue and Vue-next uses require('package.json').version indeed:

• https://github.com/vuejs/vue/blob/dev/scripts/config.js#L8
• https://github.com/vuejs/vue-next/blob/master/rollup.config.js#L10

React also seems to read the version from package.json:

• https://github.com/facebook/react/blob/master/scripts/release/utils.js#L96-L101

[pgcalixto]

I update the code in this PR to an agreed approach discussed in #800.

[GillesDebunne]

What about moving this code in a specific script? It does not seems to belong to tag.

Or maybe check versions at the beginning of release since the entire process should be stopped in case of version mismatch (which is not the case here)

[GillesDebunne]

I'm not sure grep will work on Windows for instance, but that may not be an issue.

[pgcalixto]

I thought about it too, but all these scripts have #!/usr/bin/env bash in the beginning, reinforcing the idea to run them on Bash, which afaik always has grep, even in Bash for Windows.

(also, the syntax of the scripts have other details that would only allow them to be run on Bash)

[pgcalixto]

What about moving this code in a specific script? It does not seems to belong to tag.

Or maybe check versions at the beginning of release since the entire process should be stopped in case of version mismatch (which is not the case here)

I moved it to a dedicated script, and called it in the beginning of both release and tag scripts.

[icambron]

Thanks!