I'm happy to make a PR. Also happy to help co-maintain the module if you like!

Sorry, should have done this before I created #39.

It'd be great if we could pass a domain name and prefix path, so other packages like Bundlesize could support Git repos that don't live on www.github.com, like GitHub Enterprise repos.

Coming from here siddharthkp/bundlesize#158 I checked if we can get the platform where the repository is actually hosted.

Travis : From here we can conclude that Travis supports only github.com.

Circle : There's an env variable CIRCLE_REPOSITORY_URL. Check here.

Wercker : They have WERCKER_GIT_DOMAIN. Check here

Drone : I'm not sure between DRONE_REMOTE_URL and DRONE_REPO_LINK. Check here.

We can either send repo url or the name of the hosting platform.

variables: https://woodpecker-ci.org/docs/usage/environment#built-in-environment-variables
repos: https://github.com/woodpecker-ci
website: https://woodpecker-ci.org/

https://github.com/siddharthkp/ci-env/blob/master/index.js#L82
GITHUB_REF env var contains values in the form refs/heads/master, not master itself.

Bug Report

Version: 1.5.1 (assumed 1.5.0 also)
Environment: Circle CI 2.0

Yesterday morning our Circle CI 2.0 job started failing with this error:

/home/circleci/project/node_modules/ci-env/index.js:29
  pull_request_number = process.env.CI_PULL_REQUEST.split('/').pop() // take number from returns url
                                                   ^

TypeError: Cannot read property 'split' of undefined
    at Object.<anonymous> (/home/circleci/project/node_modules/ci-env/index.js:29:52)

The failure occurs when trying to submit the initial status from the dependent repo bundle size (https://github.com/siddharthkp/bundlesize/blob/master/src/init-status.js). This error was only occurring on our main branch, but not on individual pull request runs. That makes me think there was some kind of involvement in the "picked randomly" PR numbers for merges, quoted below. Possibly the build number exists for the PR, then there's a fast-forward of the main branch, and that causes the duplication interaction. But I'm speculating there. The docs for these env variables: (https://circleci.com/docs/2.0/env-vars/#build-details)

CIRCLE_PULL_REQUESTS
Comma-separated list of pull requests this build is a part of.
CIRCLE_PULL_REQUEST
If this build is part of only one pull request, its URL will be populated here. If there was more than one pull request, it will contain one of the pull request URLs (picked randomly).
CI_PULL_REQUESTS
Same as CIRCLE_PULL_REQUESTS, only kept for the backward compatibility with 1.0.
CI_PULL_REQUEST
Same as CIRCLE_PULL_REQUEST, only kept for the backward compatibility with 1.0.

I noticed the error coincided with this repo's released version 1.5.0 and 1.5.1 yesterday, so I attempted to manually pin the version 1.4.0. I also confirmed that version 1.5.1 was being installed prior to pinning 1.4. This was successful, the error ceased.

It would be nice to support Buildkite https://buildkite.com/docs/pipelines/environment-variables

ci-env supports travis, circle, wercker and drone right now.

But, there are self hosted or containerised environments where these will not be used.

We can add support for those by supporting generic environment variables.

else if (process.env.CI === 'custom') {
   repo = process.env.CI_REPO,
   branch = process.env.CI_BRANCH
   ...
}

Currently it does not look like there's a way to get the base branch being targeted in the case of a pull request.

For reference: https://documentation.codeship.com/pro/builds-and-configuration/environment-variables/#default-environment-variables

I'll start on the implementation in a fork, but it may take some time as I'll be doing this in my spare time. Though, quickly looking through the code, it shouldn't be difficult :-)