Small function to expose environment variables to nextjs app

next.config.js

require('dotenv').config()

const getEnvWithPrefixes = (prefixes = ['REACT_APP_', 'FIREBASE_']) => {
  return Object.keys(process.env).reduce((prev, curr) => {
    if (prefixes.some(p => curr.startsWith(p))) {
      return {
        ...prev,
        [curr]: process.env[curr],
      }
    }

    return prev
  }, {})
}

module.exports = {
  env: getEnvWithPrefixes(),
}