is-following could check
if a user is following another on GitHub..

Install

$ npm install -g is-following

Usage

$ is-following tj sindresorhus
# Oops... tj is not following sindresorhus.

API

$ npm install --save is-following

Usage

const isFollowing = require('is-following')

isFollowing('user', 'targetUser')
  .then(following => {
    console.log(following) // true or false
  })

License

MIT © EGOIST