validate-commit-msg.js

#!/usr/bin/env node

/**
 * Git COMMIT-MSG hook for validating commit message
 * See https://docs.google.com/document/d/1rk04jEuGfk9kYzfqCuOlPTSJw3hEDZJTBN5E5f1SALo/edit
 *
 * Installation:
 * >> cd <angular-repo>
 * >> ln -s ../../validate-commit-msg.js .git/hooks/commit-msg
 */

'use strict';

var fs = require('fs');
var util = require('util');


var MAX_LENGTH = 100;
var PATTERN = /^(?:fixup!\s*)?(\w*)(\(([\w\$\.\*/-]*)\))?\: (.*)$/;
var IGNORED = /^WIP\:/;
var TYPES = {
 feat: true,
 fix: true,
 docs: true,
 style: true,
 refactor: true,
 perf: true,
 test: true,
 chore: true,
 revert: true
};


var error = function() {
 // gitx does not display it
 // http://gitx.lighthouseapp.com/projects/17830/tickets/294-feature-display-hook-error-message-when-hook-fails
 // https://groups.google.com/group/gitx/browse_thread/thread/a03bcab60844b812
 console.error('INVALID COMMIT MSG: ' + util.format.apply(null, arguments));
};


var validateMessage = function(message) {
 var isValid = true;

 if (IGNORED.test(message)) {
 console.log('Commit message validation ignored.');
 return true;
 }

 if (message.length > MAX_LENGTH) {
 error('is longer than %d characters !', MAX_LENGTH);
 isValid = false;
 }

 var match = PATTERN.exec(message);

 if (!match) {
 error('does not match "<type>(<scope>): <subject>" ! was: ' + message);
 return false;
 }

 var type = match[1];
 var scope = match[3];
 var subject = match[4];

 if (!TYPES.hasOwnProperty(type)) {
 error('"%s" is not allowed type !', type);
 return false;
 }

 // Some more ideas, do want anything like this ?
 // - allow only specific scopes (eg. fix(docs) should not be allowed ?
 // - auto correct the type to lower case ?
 // - auto correct first letter of the subject to lower case ?
 // - auto add empty line after subject ?
 // - auto remove empty () ?
 // - auto correct typos in type ?
 // - store incorrect messages, so that we can learn

 return isValid;
};


var firstLineFromBuffer = function(buffer) {
 return buffer.toString().split('\n').shift();
};



// publish for testing
exports.validateMessage = validateMessage;

// hacky start if not run by jasmine :-D
if (process.argv.join('').indexOf('jasmine-node') === -1) {
 var commitMsgFile = process.argv[2];
 var incorrectLogFile = commitMsgFile.replace('COMMIT_EDITMSG', 'logs/incorrect-commit-msgs');

 fs.readFile(commitMsgFile, function(err, buffer) {
 var msg = firstLineFromBuffer(buffer);

 if (!validateMessage(msg)) {
 fs.appendFile(incorrectLogFile, msg + '\n', function() {
 process.exit(1);
 });
 } else {
 process.exit(0);
 }
 });
}