dangerfile.ts

import { danger, warn, markdown, message, fail } from 'danger'

// No PR is too small to include a description of why you made a change
if (danger.github.pr.body.length < 10) {
  warn('Please include a description of your PR changes.')
}

// Keep Lockfile up to date
const packageChanged = danger.git.modified_files.includes('package.json')
const lockfileChanged = danger.git.modified_files.includes('yarn.lock')
if (packageChanged && !lockfileChanged) {
  const msg = 'Changes were made to package.json, but not to yarn.lock'
  const idea = 'Perhaps you need to run `yarn install`?'
  warn(`${msg} - <i>${idea}</i>`)
}

// Warn when there is a big PR
const bigPRThreshold = 500
if (danger.github.pr.additions + danger.github.pr.deletions > bigPRThreshold) {
  warn(':exclamation: Big PR')
  markdown(
    '> Pull Request size seems relatively large. If PR contains multiple changes, split each into separate PRs for faster, easier reviews.'
  )
}

// Congratulate when code was deleted
if (danger.github.pr.additions < danger.github.pr.deletions) {
  message(
    `✂️ Thanks for removing  ${
      danger.github.pr.deletions - danger.github.pr.additions
    } lines!`
  )
}

// Always ensure we assign someone
if (danger.github.pr.assignee === null) {
  fail(
    'Please assign someone to merge this PR, and optionally include people who should review.'
  )
}