Script to log branches merged into main with squashed commits

index.js

/*
* Utility to log branches merged into main
*
* It finds branches from commit messages because of squashed commits (and so 'git branch --merged' doesn't work),
* so results might not be accurate, use it at your own risk.
*/
import { exec as execCb } from 'child_process'

function exec (cmd) {
  return new Promise((resolve, reject) => {
    execCb(cmd, (error, stdout, stderr) => {
      if (error) {
        reject(stderr)
      } else {
        resolve(stdout)
      }
    })
  })
}

async function run (logMerged = true) {
  try {
    const current = await exec('git rev-parse --abbrev-ref HEAD')
    if (current.trim() !== 'main') {
      console.log('\n 💁  You are not in "main" branch\n')
      process.exit(1)
    }

    const output = await exec('git branch')
    const branches = output
      .split('\n')
      .map(branch => branch.slice(2))
      .filter(branch => !!branch && branch !== 'main')

    for (const branch of branches) {
      const lastCommit = await exec(`git log -n 1 ${branch}`)
      const lastCommitId = lastCommit.split('\n')[0].replace('commit ', '')
      const lastCommitMessage = (await exec(`git log --format=%B -n 1 ${lastCommitId}`)).trim()
      try {
        await exec(`git log | grep "${lastCommitMessage.replace(/"/g, '\\"')}"`)
        if (logMerged) {
          console.log(lastCommitId.slice(0, 7), branch)
        }
      } catch (e) {
        if (!logMerged) {
          console.log('Not Merged:', lastCommitId.slice(0, 7), branch)
        }
      }
    }
  } catch (e) {
    console.log('💥', e)
  }
}

run()