Git log as a json

gitlog.js

// Usage:
// 1. Paste this file into root directory
// 2. Exec `node gitlog.js > output.json` in a console
// 3. Do what you want with output.json \o/

const exec = require('child_process').exec;

// see https://git-scm.com/docs/pretty-formats for placeholder codes
const fields = {
  refs: { value: '%d', parser: a => a.replace(/[\(\)]/g, '').replace('->', ',').split(', ').map(a => a.trim()).filter(a => a) },
  commit: { value: '%H' },
  commitAbbrev: { value: '%h' },
  tree: { value: '%T' },
  treeAbbrev: { value: '%t' },
  parents: { value: '%P', parser: a => a.split(' ') },
  parentsAbbrev: { value: '%p', parser: a => a.split(' ') },
  'author.name': { value: '%an' },
  'author.email': { value: '%ae' },
  'author.timestamp': { value: '%at', parser: a => +a * 1000 },
  'committer.name': { value: '%cn' },
  'committer.email': { value: '%ce' },
  'committer.timestamp': { value: '%ct', parser: a => +a * 1000 },
  subject: { value: '%s' },
  body: { value: '%b' },
  notes: { value: '%N' }
};

const keys = Object.keys(fields);

exec(`git log --pretty=format:"%x01${keys.map(a => fields[a].value).join('%x00')}%x01" --numstat --date-order`, (err, stdout, stderr) => {
  if (err) return console.error(`exec error: ${err}`);
  const data = stdout.split('\u0001');
  const stats = data.filter((a, i) => (i + 1) % 2);
  let json = data.filter((a, i) => i % 2).map((raw, k) => {
    return Object.assign(raw.split('\u0000').reduce((mem, field, j) => {
      if (/\./.exec(keys[j])) {
        let nameParts = keys[j].split('.');
        mem[nameParts[0]] = Object.assign({}, mem[nameParts[0]], { [nameParts[1]]: fields[keys[j]].parser ? fields[keys[j]].parser(field) : field.trim() });
      } else {
        mem[keys[j]] = fields[keys[j]].parser ? fields[keys[j]].parser(field) : field.trim();
      }
      return mem;
    }, {}), {
        // Add parsed stats of each commit
        stats: stats[k + 1].split('\n').filter(a => a).map(a => {
          let b = a.split('\t');
          return {
            additions: +b[0], deletions: +b[1], file: b[2]
          };
        })
      });
  });

  console.log(JSON.stringify(json));
});