dotenv not reading variables inside .env file

I’m trying to use dotenv to load the following .env file:

PORT=4000
BASE_URL=http://127.0.0.1:${PORT}/

require('dotenv').config('.env')

For some reasons, dotenv does not resolve ${PORT} to 4000, instead it just returns a plain string like this:

{
  parsed: {
    PORT: '4000',
    BASE_URL: 'http://127.0.0.1:$PORT/',
  }
}

How can I make dotenv read variables inside .env file?

>Solution :

You can use dotenv-expand because dotenv doesn’t support variable substitution using ${} syntax.

to use dotenv-expand install

npm install dotenv-expand

add require dotenvExpand keep the same .env file with ${} syntax

var dotenv = require("dotenv");
var dotenvExpand = require("dotenv-expand");

var result = dotenv.config();
dotenvExpand.expand(result);

console.log(result.parsed);

The output will return like:

{
  PORT: '4000',
  BASE_URL: 'http://127.0.0.1:4000/'
}

Output: