#!/usr/bin/env node
/**
* Simple changelog generator from git commits
* Filters commits by type (feat, fix, perf, breaking) and generates minimal markdown
*/
import { execSync } from 'child_process';
import fs from 'fs';
import path from 'path';
import { fileURLToPath } from 'url';
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
const CHANGELOG_FILE = path.join(__dirname, '..', 'CHANGELOG.md');
// Commit types to include in changelog
const IMPORTANT_TYPES = {
feat: 'Features',
fix: 'Bug Fixes',
perf: 'Performance Improvements',
};
/**
* Execute git command and return output
*/
function git(command) {
try {
return execSync(`git ${command}`, { encoding: 'utf-8' }).trim();
} catch (error) {
console.error(`Git command failed: ${command}`);
return '';
}
}
/**
* Get all tags sorted by version
*/
function getTags() {
const tags = git('tag -l "v*" --sort=-version:refname');
return tags ? tags.split('\n').filter(Boolean) : [];
}
/**
* Get commits between two refs
*/
function getCommitsBetween(from, to) {
const range = from ? `${from}..${to}` : to;
const separator = '###COMMIT_SEP###';
const log = git(`log ${range} --pretty=format:"${separator}%H|%s|%b"`);
if (!log) return [];
return log
.split(separator)
.filter(Boolean)
.map(commit => {
const lines = commit.trim().split('\n');
const firstLine = lines[0];
const [hash, subject, ...bodyParts] = firstLine.split('|');
const body = [...bodyParts, ...lines.slice(1)].join('\n');
return {
hash: hash ? hash.substring(0, 7) : '',
subject: subject || '',
body: body || ''
};
})
.filter(c => c.hash && c.subject);
}
/**
* Parse commit subject to extract type and description
*/
function parseCommit(commit) {
const match = commit.subject.match(/^(\w+)(?:\(([^)]+)\))?: (.+)$/);
if (!match) return null;
const [, type, scope, description] = match;
const isBreaking = commit.body.includes('BREAKING CHANGE') || commit.subject.includes('!');
return {
type,
scope,
description,
isBreaking,
hash: commit.hash,
};
}
/**
* Filter commits to only important ones
*/
function filterImportantCommits(commits) {
const parsed = commits
.map(parseCommit)
.filter(Boolean);
const important = parsed.filter(
c => IMPORTANT_TYPES[c.type] || c.isBreaking
);
return important;
}
/**
* Group commits by type
*/
function groupCommits(commits) {
const groups = {};
// Add breaking changes first if any
const breaking = commits.filter(c => c.isBreaking);
if (breaking.length > 0) {
groups['Breaking Changes'] = breaking;
}
// Group by type
Object.entries(IMPORTANT_TYPES).forEach(([type, label]) => {
const typeCommits = commits.filter(c => c.type === type && !c.isBreaking);
if (typeCommits.length > 0) {
groups[label] = typeCommits;
}
});
return groups;
}
/**
* Format commits as markdown
*/
function formatChangelog(version, date, groups) {
let markdown = `## [${version}] - ${date}\n\n`;
Object.entries(groups).forEach(([label, commits]) => {
markdown += `### ${label}\n\n`;
commits.forEach(commit => {
const scope = commit.scope ? `**${commit.scope}**: ` : '';
markdown += `- ${scope}${commit.description} (${commit.hash})\n`;
});
markdown += '\n';
});
return markdown;
}
/**
* Get date for a tag
*/
function getTagDate(tag) {
const date = git(`log -1 --format=%ai ${tag}`);
return date ? date.split(' ')[0] : new Date().toISOString().split('T')[0];
}
/**
* Generate changelog for a specific version
*/
function generateVersionChangelog(currentTag, previousTag) {
const commits = getCommitsBetween(previousTag, currentTag);
const important = filterImportantCommits(commits);
if (important.length === 0) {
return null;
}
const groups = groupCommits(important);
const version = currentTag.replace(/^v/, '');
const date = getTagDate(currentTag);
return formatChangelog(version, date, groups);
}
/**
* Generate full changelog from all tags
*/
function generateFullChangelog() {
const tags = getTags();
if (tags.length === 0) {
console.error('No tags found in repository');
return null;
}
let changelog = `# Changelog\n\n`;
changelog += `All notable changes to this project will be documented in this file.\n\n`;
changelog += `The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).\n\n`;
for (let i = 0; i < tags.length; i++) {
const currentTag = tags[i];
const previousTag = tags[i + 1] || null;
const versionLog = generateVersionChangelog(currentTag, previousTag);
if (versionLog) {
changelog += versionLog;
}
}
return changelog;
}
/**
* Update CHANGELOG.md file
*/
function updateChangelogFile(content) {
fs.writeFileSync(CHANGELOG_FILE, content, 'utf-8');
console.log(`✓ Updated ${CHANGELOG_FILE}`);
}
/**
* Main function
*/
function main() {
const args = process.argv.slice(2);
const command = args[0];
if (command === '--help' || command === '-h') {
console.log(`
Usage: generate-changelog.js [options]
Options:
--version <tag> Generate changelog for specific version
--output Output to stdout instead of file
--help, -h Show this help message
Examples:
generate-changelog.js # Generate full changelog and update file
generate-changelog.js --version v3.0.0 # Generate changelog for v3.0.0
generate-changelog.js --output # Output to stdout
`);
return;
}
const versionIndex = args.indexOf('--version');
const outputToStdout = args.includes('--output');
let changelog;
if (versionIndex !== -1) {
const tag = args[versionIndex + 1];
if (!tag) {
console.error('Error: --version requires a tag argument');
process.exit(1);
}
const tags = getTags();
const currentIndex = tags.indexOf(tag);
if (currentIndex === -1) {
console.error(`Error: Tag ${tag} not found`);
process.exit(1);
}
const previousTag = tags[currentIndex + 1] || null;
changelog = generateVersionChangelog(tag, previousTag);
if (!changelog) {
console.log(`No notable changes for ${tag}`);
return;
}
} else {
changelog = generateFullChangelog();
}
if (!changelog) {
console.error('Failed to generate changelog');
process.exit(1);
}
if (outputToStdout) {
console.log(changelog);
} else {
updateChangelogFile(changelog);
}
}
// Run main if executed directly
if (import.meta.url === `file://${process.argv[1]}`) {
main();
}
export {
generateFullChangelog,
generateVersionChangelog,
getTags,
};
