index.js

module.exports = app => {
  app.on('pull_request.opened', async context => {
    const files = await context.github.pullRequests.getFiles(context.issue())
    const config = await context.config('config.yml')
    const docs = files.data.find(function (file) {
      let targetFile

      if (config.updateDocsTargetFiles) {
        targetFile = config.updateDocsTargetFiles.find(function (item) {
          if (file.filename.startsWith(item) || file.filename.includes(item)) {
            return item
          }
        })
        return targetFile
      } else {
        if (file.filename.startsWith('README') || file.filename.includes('docs/')) {
          return file
        }
      }
    })

    if (!docs) {
      // Get config.yml and comment that on the PR
      try {
        const title = context.payload.pull_request.title
        let whiteList
        if (config.updateDocsWhiteList) {
          whiteList = config.updateDocsWhiteList.find(function (item) {
            if (title.toLowerCase().includes(item.toLowerCase())) {
              return item
            }
          })
        }
        // Check to make sure it's not whitelisted (ie bug or chore)
        if (!whiteList) {
          const template = config.updateDocsComment
          return context.github.issues.createComment(context.issue({body: template}))
        }
      } catch (err) {
        if (err.code !== 404) {
          throw err
        }
      }
    }
  })
}