Load or set environment variables in Node.js without dotenv or any third package.

const http =require('http');    const { port, environment } = require('./config').getEnv();    http.createServer().listen(port, async () => {      console.log(`env: ${environment}`);      console.log(`server is running on ${port} port`);    }).on('error', (e) => console.log(e));

const fs = require('fs');    const path = require('path');    const { parseBuffer } = require('./helpers/parse');    const getEnv = () => {      const envFilePath = path.join(__dirname, '.env');      const bufferEnv = fs.readFileSync(envFilePath);      const envObject = parseBuffer(bufferEnv);      Object.keys((envObject || {})).map(key => {        if(!process.env[key] && process.env[key] !== envObject[key]){          process.env[key] = envObject[key];        }      });      const version = process.env.VERSION;      const environment = process.env.ENVIRONMENT;      const port = process.env.PORT;      return {        version,        environment,        port,      }    }    module.exports = {      getEnv    }

VERSION=v1.0.0ENVIRONMENT=localPORT=3001

const NEWLINES_MATCH = /\r
|
|\r/    const NEWLINE = '
'    const RE_INI_KEY_VAL = /^\s*([\w.-]+)\s*=\s*(.*)?\s*$/    const RE_NEWLINES = /\
/g    const parseBuffer = (src) => {      const obj = {};      src.toString().split(NEWLINES_MATCH).forEach((line, idx) => {        // matching "KEY" and "VAL" in "KEY=VAL"        const keyValueArr = line.match(RE_INI_KEY_VAL);        // matched?        if(keyValueArr != null){          const key = keyValueArr[1];          // default undefined or missing values to empty string          let val = (keyValueArr[2] || '');          const end = val.length -1;          const isDoubleQuoted = val[0] === '"' && val[end] === '"';          const isSingleQuoted = val[0] === "'" && val[end] === "'";          // if single or double quoted, remove quotes           if(isSingleQuoted || isDoubleQuoted) {            val = val.substring(1, end);            // if double quoted, expand newlines            if(isDoubleQuoted){              val = val.replace(RE_NEWLINES, NEWLINE);            }                  } else {            //  remove surrounding whitespace            val = val.trim();          }          obj[key] = val;        }      });      return obj;    }    module.exports = {      parseBuffer    }