Converts a .env file to a .env.js file

envFileToJS.js

#!/usr/bin/env node
const fs = require('fs');
const path = require('path');
const os = require('os');

/**
 * Writes bash env variables to a .env.js file
 */
// const _bashEnvToEnvFileJs = () => {
//   /** Destination Env file path */
//   const [filePath = '.env.js', includesStr] = process.argv.slice(2);

//   /** Regexes to include */
//   const includes = [
//     'NODE_ENV',
//     '^REACT_APP_',
//     ...includesStr ? includesStr.split(',') : [],
//   ];

//   /** Current env vars keys */
//   const keys = Object.keys(process.env);
//   /** Keys to include in the final file */
//   const keysToInclude = [];

//   /** Pick up the env var keys */
//   for (let i = 0; i < keys.length; i++) {
//     const key = keys[i];
//     /** Check if key should be included */
//     for (let j = 0; j < includes.length; j++) {
//       const includeRegex = includes[j];
//       if (key.match(includeRegex)) {
//         /** Include key */
//         keysToInclude.push(key);
//       }
//     }
//   }

//   /** Destination env file text */
//   let fileText = ``;

//   /** Build env vars */
//   for (let i = 0; i < keysToInclude.length; i++) {
//     fileText += `exports.${keysToInclude[i]} = '${process.env[keysToInclude[i]]}';\n`;
//   }

//   /** Write destination env file */
//   fs.writeFileSync(path.resolve(filePath), fileText);
// };

/**
 * Replicates a normal .env file to a .env.js file
 */
const _envFileToEnvFileJs = (
  fromFilePath = '.env',
  toFilePath = '.env.js',
) => {
  const envFileText = fs.readFileSync(path.resolve(fromFilePath), 'utf8');

  const envVars = envFileText
    .trim()
    .split(os.EOL)
    .map(str => str.trim())
    .filter(Boolean)
    /* to JSON */
    .reduce((prevValue, currentValue) => {
      const delimiterIndex = currentValue.indexOf('='); // Gets the first index where an = occours
      /* skip if comment or invalid line */
      if (currentValue.startsWith('#') || delimiterIndex === -1) {
        return prevValue;
      }
      const key = currentValue.substr(0, delimiterIndex); // Gets the first key
      const value = currentValue.substr(delimiterIndex + 1); // Gets the value
      /* skip if invalid line */
      if (!key || !value) {
        return prevValue;
      }
      /* Add new env var */
      return {
        ...prevValue,
        [key]: value,
      };
    }, {});

  let fileText = ``;

  /** Build env vars */
  Object.keys(envVars).forEach(key => {
    fileText += `exports.${key} = '${envVars[key]}';\n`;
  });

  fs.writeFileSync(path.resolve(toFilePath), fileText);
};

const main = () => {
  _envFileToEnvFileJs();
};

main();