createReleaseNotes.js

const { exec } = require('child_process');

const verbData = {
  chore: {
    label: 'Chores',
    renderOrder: 4,
  },
  feat: {
    label: 'New Features',
    renderOrder: 0,
  },
  fix: {
    label: 'Fixes',
    renderOrder: 1,
  },
  improv: {
    label: 'Improvements',
    renderOrder: 2,
  },
  perf: {
    label: 'Performance Fixes',
    renderOrder: 3,
  },
  refactor: {
    label: 'Refactoring',
  },
  style: {
    label: 'Style Changes',
  },
  test: {
    label: 'Tests',
  },
};

const verbs = Object.keys(verbData);
const commitFormat = `^(${verbs.join('|')})(\\((\\w+)\\))?:\\s*(.+)$`;
const capitalize = str => str.charAt(0).toUpperCase() + str.slice(1);

exec(`git log $(git describe --tags --abbrev=0)..HEAD --pretty=format:'%B'`, (err, linesAsBuffer, stderr) => {
  if (err) {
    console.log('\x1b[33m%s\x1b[0m', 'Error retrieving commits:');
    console.log('\x1b[33m%s\x1b[0m', stderr);
    process.exit(1);
  }

  const lines = linesAsBuffer.toString().split('\n').reverse();

  const releaseInfo = lines
    .map(line => line.trim())
    .filter(Boolean)
    .map(line => line.split('\n').join(' '))
    .map(line => new RegExp(commitFormat, 'gi').exec(line))
    .filter(Boolean)
    .map(matchedResults => ({
      verb: matchedResults[1],
      scope: matchedResults[3] || 'miscellaneous',
      body: matchedResults[4],
    }))
    .reduce((result, current) => {
      // verb -> scope -> body
      result[current.verb] = result[current.verb] || {};
      const scopesByVerb = result[current.verb];
      scopesByVerb[current.scope] = scopesByVerb[current.scope] || [];
      const scopeItems = scopesByVerb[current.scope];
      scopeItems.push(current.body);
      return result;
    }, {});

  const releaseNotes = Object.entries(verbData)
    .filter(([key, info]) => info.renderOrder !== undefined)
    .sort(([key1, info1], [key2, info2]) => info1.renderOrder - info2.renderOrder)
    .filter(([key, info]) => releaseInfo[key])
    .map(([key, info]) => [
      key,
      info,
      Object.entries(releaseInfo[key]).sort()
    ])
    .reduce((result, [key, info, scopes]) => {
      result.push(`## ${info.label}`);
      scopes.forEach(([name, commits]) => {
        result.push(`### ${capitalize(name)}`);
        commits.forEach(commit => result.push(`* ${commit}`));
      });
      return result;
    }, [])
    .map(line => line
      // Now escape the multiline string for output to GitHub Actions.
      .replace(/"/gi, '\\"')
      .replace(/'/gi, `'\\''`) // The wonders of bash...
      .replace(/%/gi, '%25')
      .replace(/\n/gi, '\\n')
      .replace(/\r/gi, '\\r')
    )
    .join('\\n')
  ;

  console.log(`::set-output name=release_notes::${releaseNotes}`);
  process.exit(0);

});