dangerfile.js

import { danger, fail, warn, markdown } from 'danger';
import { any } from 'ramda';
import fs from 'fs';

// ("/href/thing", "name") to "<a href="/href/thing">name</a>"
const createLink = (href: string, text: string): string => `<a href='${href}'>${text}</a>`;

// ["1", "2", "3"] to "1, 2 and 3"
const toSentence = (array: Array<string>): string => {
  if (array.length === 1) {
    return array[0];
  }
  return `${array.slice(0, array.length - 1).join(', ')} and ${array.pop()}`;
};

const linkableFiles = (paths) => {
  const repoURL = danger.github.pr.head.repo.html_url;
  const { ref } = danger.github.pr.head;
  const links = paths.map(path => createLink(`${repoURL}/blob/${ref}/${path}`, path));
  return toSentence(links);
};

// Raise about missing code inside files
const raiseIssueAboutPaths = (
  type: Function,
  paths: string[],
  codeToInclude: string,
) => {
  if (paths.length > 0) {
    const files = linkableFiles(paths);
    const strict = `<code>${codeToInclude}</code>`;
    type(`Please ensure that ${strict} is enabled on: ${files}`);
  }
};

// make sure someone else reviews these changes
const someoneAssigned = danger.github.pr.assignee;
if (someoneAssigned === null) {
  warn(
    'Please assign someone to merge this PR, and optionally include people who should review.',
  );
}

// Make sure there are changelog entries
const hasChangelog = danger.git.modified_files.includes('CHANGELOG.md') ||
  danger.git.created_files.includes('CHANGELOG.md');
if (!hasChangelog) {
  warn('No Changelog changes!');
}

// only look in the /src/ folder
const jsModifiedFiles = danger.git.created_files
  .filter(path => any(x => x.includes('src/'), path))
  .filter(path => path.endsWith('js'));
const hasAppChanges = jsModifiedFiles.length > 0;

const jsTestChanges = jsModifiedFiles.filter(filepath =>
  filepath.includes('__tests__'));
const hasTestChanges = jsTestChanges.length > 0;

// Warn when there is a big PR
const bigPRThreshold = 500;
if (danger.github.pr.additions + danger.github.pr.deletions > bigPRThreshold) {
  warn(':exclamation: Big PR');
}

// XXX add in License header
// https://github.com/facebook/jest/blob/master/dangerfile.js#L58

// Warn if there are library changes, but not tests
if (hasAppChanges && !hasTestChanges) {
  warn(
    "There are library changes, but not tests. That's OK as long as you're refactoring existing code",
  );
}

// Be careful of leaving testing shortcuts in the codebase
const onlyTestFiles = jsTestChanges.filter((x) => {
  const content = fs.readFileSync(x).toString();
  return content.includes('it.only') || content.includes('describe.only');
});
raiseIssueAboutPaths(fail, onlyTestFiles, 'an `only` was left in the test');

// Politely ask for their name on the entry too
if (hasChangelog) {
  const changelogDiff = danger.git.diffForFile('changelog.md');
  const contributorName = danger.github.pr.user.login;
  if (changelogDiff && changelogDiff.indexOf(contributorName) === -1) {
    warn(
      `Please add your GitHub name ("${
        contributorName
      }") to the changelog entry.`,
    );
  }
}

// Warns if there are changes to package.json without changes to yarn.lock.
const packageChanged = any(
  x => x.includes('package.json'),
  danger.git.modified_files,
);
const lockfileChanged = any(
  x => x.includes('yarn.lock'),
  danger.git.modified_files,
);
if (packageChanged && !lockfileChanged) {
  const message = 'Changes were made to package.json, but not to yarn.lock';
  const idea = 'Perhaps you need to run `yarn install`?';
  warn(`${message} - <i>${idea}</i>`);
}

// show release QA checklist if it be a release
const hasReleaseLabel = danger.github &&
  danger.github.issue &&
  danger.github.issue.labels &&
  danger.github.issue.labels.find(x => x.name && x.name === 'Release');

if (hasReleaseLabel) {
  const checklist = fs.readFileSync('./.travis/QA.md');
  markdown(checklist);
}