Add @netlify/heuristics package

We need a nice way to figure out different information about a project from its source code.

@netlify/heuristics (working title) would be the module that detects what kind of a project the repo is, including:

• The type of static generator used
• The functions setup (what runtime JS or Go)
• What binaries are used in the build.command See https://github.com/netlify/netlify-build/tree/master/packages/%40netlify-build/src/heuristics
• If nvmrc is set what version of node does this project expect
• Is there a requirements.txt file to indication its a python based project
• Information (if available) on what the remove git provider is, github/gitlab/bitbucket.

Any information that we need to:

1. Use in the scaffolding flow
2. Use in netlify dev
3. Use in netlify build. Plugins might want to have this heuristic information

Currently there is https://github.com/netlify/cli/tree/master/src/detectors living in the CLI and https://github.com/netlify/netlify-build/tree/master/packages/%40netlify-build/src/heuristics inside the build package.

Todo:

• Extract this into a package in this repo
• Include & potentially refactor detectors
• Include additional information we have access to listed above & any other ideas that we think would be handy for consumers (in build, build plugins, & netlify dev)
• Use dependency in CLI

---

Notes: https://github.com/netlify/cli/tree/master/src/detectors is using alot of sync calls and the API might need to be revisited to avoid false positives.

[erquhart]

Super late here, but good point @lesliecdubs. Ideally we wouldn’t have two different implementations of the same logic. Want to start exploring CLI and UI parity and code reuse more.

[lesliecdubs]

FYI in case this is useful, we already have some very basic heuristics set up in the app. As swyx mentioned, we only use them right now to detect a user’s build command and publish folder in the “create a new site” flow once a repo is linked.

https://github.com/netlify/netlify-react-ui/blob/master/src/lib/heuristics/automation.js