release-notes.js

const got = require('got');

async function main() {
  const res = await got(
    'https://api.github.com/repos/jaredpalmer/after.js/releases',
    {
      responseType: 'json',
    }
  );

  const allReleases = res.body
    .map(({ id, tag_name, created_at, body }) => ({
      id,
      tag_name,
      created_at,
      body: body
        .replace(/\r\n/g, '\n')
        .split('\n')
        .map(e => e.trim()),
    }))
    .sort((a, b) => a.created_at.localeCompare(b.created_at));

  const targetVersion = /v(.*?-)/
    .exec(allReleases.filter(e => /v.*?-/.exec(e.tag_name)).pop().tag_name)
    .pop();

  const releases = allReleases.filter(v => v.tag_name.includes(targetVersion));

  const lineItems = {
    '### Minor Changes': [],
    '### Patches': [],
    '### Credits': [],
  };

  Object.keys(lineItems).forEach(header => {
    releases.forEach(release => {
      const headerIndex = release.body.indexOf(header);
      if (!~headerIndex) return;

      let headerLastIndex = release.body
        .slice(headerIndex + 1)
        .findIndex(v => v.startsWith('###'));

      if (~headerLastIndex) {
        headerLastIndex = headerLastIndex + headerIndex;
      } else {
        headerLastIndex = release.body.length - 1;
      }

      if (header === '### Credits') {
        release.body.slice(headerIndex, headerLastIndex + 1).forEach(e => {
          const re = /@[a-z\d](?:[a-z\d]|-(?=[a-z\d])){0,38}/gi;
          let m;
          do {
            m = re.exec(e);
            if (m) {
              lineItems[header].push(m.pop());
            }
          } while (m);
        });
      } else {
        release.body.slice(headerIndex, headerLastIndex + 1).forEach(e => {
          if (!e.startsWith('-')) {
            return;
          }

          lineItems[header].push(e);
        });
      }
    });
  });

  let finalMessage = [];
  Object.keys(lineItems).forEach(header => {
    let items = lineItems[header];
    if (!items.length) {
      return;
    }

    finalMessage.push(header);
    finalMessage.push('');

    if (header === '### Credits') {
      items = [...new Set(items)];
      let creditsMessage = `Huge thanks to `;
      if (items.length > 1) {
        creditsMessage += items.slice(0, items.length - 1).join(`, `);
        creditsMessage += `, and `;
      }

      creditsMessage += items[items.length - 1];
      creditsMessage += ` for helping!`;

      finalMessage.push(creditsMessage);
    } else {
      items.forEach(e => finalMessage.push(e));
    }

    finalMessage.push('');
  });

  const firstVersion = releases[0].tag_name;
  const lastVersion = releases[releases.length - 1].tag_name;

  // Add compare link
  finalMessage.push(
    `https://github.com/jaredpalmer/after.js/compare/${firstVersion}...${lastVersion}`
  );

  return {
    version: targetVersion.slice(0, -1),
    firstVersion,
    lastVersion,
    content: finalMessage.join('\n'),
  };
}
Promise.resolve()
  .then(main)
  .then(notes => console.log(String(notes.content)));