Detect what kind of CI environment the program is in

const ciDetect = require('@npmcli/ci-detect')
// false if not in CI
// otherwise, a string indicating the CI environment type
const inCI = ciDetect()

Returns one of the following strings, or false if none match, by looking at the appropriate environment variables.

• 'gerrit' Gerrit
• 'gitlab' GitLab
• 'circleci' Circle-CI
• 'semaphore' Semaphore
• 'drone' Drone
• 'github-actions' GitHub Actions
• 'tddium' TDDium
• 'jenkins' Jenkins
• 'bamboo' Bamboo
• 'gocd' GoCD
• 'wercker' Oracle Wercker
• 'woodpecker' Woodpecker CI
• 'netlify' Netlify
• 'now-github' Zeit.co's Now for GitHub deployment service
• 'now-bitbucket' Zeit.co's Now for BitBucket deployment service
• 'now-gitlab' Zeit.co's Now for GitLab deployment service
• 'now' Zeit.co's Now service, but not GitHub/BitBucket/GitLab
• 'azure-pipelines' Azure Pipelines
• 'bitbucket-pipelines' Bitbucket Pipelines
• 'bitrise' Bitrise
• 'buddy' Buddy
• 'buildkite' Buildkite
• 'cirrus' Cirrus CI
• 'dsari' dsari CI
• 'screwdriver' Screwdriver CI
• 'strider' Strider CI
• 'taskcluster' Mozilla Taskcluster
• 'hudson' Hudson CI
• 'magnum' Magnum CI
• 'nevercode' Nevercode
• 'render' Render CI
• 'sail' Sail CI
• 'shippable' Shippable
• 'heroku' Heroku
• 'codeship' CodeShip
• 'teamcity' TeamCity
• 'vercel' Vercel
• 'vercel-github' Vercel GitHub
• 'vercel-gitlab' Vercel Gitlab
• 'vercel-bitbucket' Vercel Bitbucket
• Anything that sets the CI_NAME environment variable will return the value as the result. (This is how CodeShip is detected.)
• 'travis-ci' Travis-CI - A few other CI systems set TRAVIS=1 in the environment, because devs use that to indicate "test mode", so this one can get some false positives, and is tested later in the process to minimize this effect.
• 'aws-codebuild' AWS CodeBuild
• 'builder' Google Cloud Builder - This one is a bit weird. It doesn't really set anything that can be reliably detected except BUILDER_OUTPUT, so it can get false positives pretty easily.
• 'custom' anything else that sets CI environment variable to either '1' or 'true'.

Note that since any program can set or unset whatever environment variables they want, this is not 100% reliable.

Also, note that if your program does different behavior in CI/test/deployment than other places, then there's a good chance that you're doing something wrong!

But, for little niceties like setting colors or other output parameters, or logging and that sort of non-essential thing, this module provides a way to tweak without checking a bunch of things in a bunch of places. Mostly, it's a single place to keep a note of what CI system sets which environment variable.