Firebase deploy only changed functions

deploy.js

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

async function deployOnlyChangedFunctions() {
  const { stdout: shaOfLostCommit } = await exec('git rev-parse HEAD');
  const { stdout: changedFiles } = await exec(`git log -m -1 --name-only --pretty="format:" ${shaOfLostCommit}`);
  const functionsFolder = 'functions/modules/'
  const filenames = changedFiles.split('\n')
  .filter((line) => line.startsWith(functionsFolder))
  .map((line) => line.split('/')[2])
  .filter((line) => !line.includes('.'))
  .map((line) => {
    return line
    .replace(/\-[a-z]/g, match => match.toUpperCase())
    .split('-').join('')
  })

  const modules = [...new Set(filenames)].join(',')
  const deployScript = `firebase deploy --only functions:${modules}`

  await exec(deployScript)
}

deployOnlyChangedFunctions();