changelog-generator.js

#!/usr/bin/env node

'use strict';

const levenshtein = require('fast-levenshtein');

const argv = require('yargs')
    .usage('$0 [args]', 'Generate a React Native changelog from the commits and PRs')
    .options({
        'base': {
            alias: 'b',
            describe: 'the base version branch or commit to compare against (most often, this is the current stable)',
            demandOption: true
        },
        'compare': {
            alias: 'c',
            describe: 'the new version branch or commit (most often, this is the release candidate)',
            demandOption: true
        }
    })
  .version(false)
  .help('help')
  .argv

const base = argv.base;
const compare = argv.compare;

function fetchJSON(host, path) {
  return new Promise((resolve, reject) => {
    let data = '';

    require('https').get({
      host,
      path,
      headers: { 'User-Agent': 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)' },
    }).on('response', response => {
      response.on('data', chunk => {
        data += chunk;
      });

      response.on('end', () => {
        try {
          const json = JSON.parse(data);
          resolve(json);
        } catch (e) {
          reject(e);
        }
      });

      response.on('error', error => {
        reject(error);
      });
    });
  });
}

function filterCICommits(commits) {
  return commits.filter(item => {
    const text = item.commit.message.toLowerCase();
    return !(text.includes('travis') || text.includes('circleci') || text.includes('circle ci') || text.includes('bump version numbers'));
  });
}
function filterRevertCommits(commits) {
  let revertCommits = [];
  const revertCommitIndicators = ['revert "', 'back out "'];
  const filteredCommits = commits.filter(item => {
    let text = item.commit.message.split('\n')[0].toLowerCase();
    if(revertCommitIndicators.some(indicator => text.includes(indicator))) {
      revertCommitIndicators.forEach(indicator => {
        text = text.replace(indicator, "");
      });
      revertCommits.push(text);
      return false;
    }
    return true;
  }).filter(item => {
    let text = item.commit.message.split('\n')[0].toLowerCase();
    revertCommits.forEach(revertCommit => {
      if(levenshtein.get(text, revertCommit) < 0.5 * revertCommit.length) {
        revertCommits = revertCommits.filter(function(e) { return e !== revertCommit });
        return false;
      }
    });
    return true;
  });
  if(revertCommits.length > 0) console.warn("Was unable to find the mate for the following revert commits: " + revertCommits + "; you will need to manually remove this from below.");
  return filteredCommits;
}

function isAndroidCommit(change) {
  return /\b(android|java)\b/i.test(change) || /android/i.test(change);
}

function isIOSCommit(change) {
  return /\b(ios|xcode|swift|objective-c|iphone|ipad)\b/i.test(change) || /ios\b/i.test(change) || /\brct/i.test(change);
}

function isAdded(change) {
  return /\b(add|adds|added|enhancement)\b/i.test(change);
}

function isChanged(change) {
  return /\b(changes|changed)\b/i.test(change);
}

function isDeprecated(change) {
    return /\b(deprecated|deprecate)\b/i.test(change);
}

function isRemoved(change) {
    return /\b(remove|removed)\b/i.test(change);
}

function isFixed(change) {
    return /\b(fix|fixes|fixed)\b/i.test(change);
}
  
function isSecurity(change) {
    return /\b(security)\b/i.test(change);
  }

function getChangeMessage(item) {
  const commitMessage = item.commit.message.split('\n');
  const entry = commitMessage.find(a => /\[ios\]|\[android\]|\[general\]/i.test(a)) || commitMessage[0];
  const authorSection = `([${item.sha.slice(0, 7)}](https://github.com/facebook/react-native/commit/${item.sha.slice(0, 7)})${item.author ? ' by [@' + item.author.login + '](https://github.com/' + item.author.login + ')' : ''})`;
  return `- ${entry} ${authorSection}`;
}

function getChangelogDesc(commits) {
  const acc = {
    added: { android: [], ios: [], general: [] },
    changed: { android: [], ios: [], general: [] },
    deprecated: { android: [], ios: [], general: [] },
    removed: { android: [], ios: [], general: [] },
    fixed: { android: [], ios: [], general: [] },
    security: { android: [], ios: [], general: [] },
    unknown: { android: [], ios: [], general: [] },
  };

  commits.forEach(item => {
    const change = item.commit.message;
    const message = getChangeMessage(item);

    if (isAdded(change)) {
      if (isAndroidCommit(change)) {
        acc.added.android.push(message);
      } else if (isIOSCommit(change)) {
        acc.added.ios.push(message);
      } else {
        acc.added.general.push(message);
      }
    } else if (isChanged(change)) {
        if (isAndroidCommit(change)) {
          acc.changed.android.push(message);
        } else if (isIOSCommit(change)) {
          acc.changed.ios.push(message);
        } else {
          acc.changed.general.push(message);
        }
      } else if (isDeprecated(change)) {
        if (isAndroidCommit(change)) {
          acc.deprecated.android.push(message);
        } else if (isIOSCommit(change)) {
          acc.deprecated.ios.push(message);
        } else {
          acc.deprecated.general.push(message);
        }
      } else if (isRemoved(change)) {
        if (isAndroidCommit(change)) {
          acc.removed.android.push(message);
        } else if (isIOSCommit(change)) {
          acc.removed.ios.push(message);
        } else {
          acc.removed.general.push(message);
        }
      } else if (isFixed(change)) {
        if (isAndroidCommit(change)) {
          acc.fixed.android.push(message);
        } else if (isIOSCommit(change)) {
          acc.fixed.ios.push(message);
        } else {
          acc.fixed.general.push(message);
        }
      } else if (isSecurity(change)) {
        if (isAndroidCommit(change)) {
          acc.security.android.push(message);
        } else if (isIOSCommit(change)) {
          acc.security.ios.push(message);
        } else {
          acc.security.general.push(message);
        }
      } else {
      if (isAndroidCommit(change)) {
        acc.unknown.android.push(message);
      } else if (isIOSCommit(change)) {
        acc.unknown.ios.push(message);
      } else {
        acc.unknown.general.push(message);
      }
    }
  });

  return acc;
}

function buildMarkDown(data) {
  return `

## [${argv.compare}.0]

### Added

${data.added.general.join('\n')}

#### Android specific

${data.added.android.join('\n')}

#### iOS specific

${data.added.ios.join('\n')}

### Changed

${data.changed.general.join('\n')}

#### Android specific

${data.changed.android.join('\n')}

#### iOS specific

${data.changed.ios.join('\n')}

### Deprecated

${data.deprecated.general.join('\n')}

#### Android specific

${data.deprecated.android.join('\n')}

#### iOS specific

${data.deprecated.ios.join('\n')}

### Removed

${data.removed.general.join('\n')}

#### Android specific

${data.removed.android.join('\n')}

#### iOS specific

${data.removed.ios.join('\n')}

### Fixed

${data.fixed.general.join('\n')}

#### Android specific

${data.fixed.android.join('\n')}

#### iOS specific

${data.fixed.ios.join('\n')}

### Security

${data.security.general.join('\n')}

#### Android specific

${data.security.android.join('\n')}

#### iOS specific

${data.security.ios.join('\n')}

### Unknown

${data.unknown.general.join('\n')}

#### Android Unknown

${data.unknown.android.join('\n')}

#### iOS Unknown

${data.unknown.ios.join('\n')}
`;
}

fetchJSON('api.github.com', '/repos/facebook/react-native/compare/' + base + '...' + compare)
  .then(data => data.commits)
  .then(filterCICommits)
  .then(filterRevertCommits)
  .then(getChangelogDesc)
  .then(buildMarkDown)
  .then(data => console.log(data))
  .catch(e => console.error(e));