git-squash.js

#!/usr/bin/env node

const { execSync, spawn } = require('child_process');
const chalk = require('chalk');

function hasChangesInRepo() {
        return execSync('git status --porcelain').toString().length > 0;
}

if (hasChangesInRepo()) {
        console.error('Error: there are changes in the repo. Can\'t start squashing.');
        return;
}

const lastCommitMessage = execSync('git log -1 --pretty=%B').toString().trim();
if (!lastCommitMessage) {
        throw new Error('Unable to get message of last commit');
}

execSync('git reset --soft HEAD~2');
spawn('git', ['commit', '-m', lastCommitMessage], {stdio:'inherit'});