contributors.js

const { readFileSync } = require('fs');
const { execSync } = require('child_process');

const lastVersion = '14.0.0';

const repos = [
  '~/Projects/angular',
  '~/Projects/components',
  '~/Projects/angular-cli'
];

const contributorsCommand = `git log ${lastVersion}.. --format="%aN <%aE>" --reverse | perl -e 'my %dedupe; while (<STDIN>) { print unless $dedupe{$_}++}'`;

const all = new Set(repos.reduce((accum, repo) => {
  return accum + execSync(`cd ${repo} && ${contributorsCommand}`).toString();
}, '').split('\n').filter(e => !!e));


console.log(all.size);