Is the value from .env undefined?

Question

Node.js

Hello! In my application on Angular 2+ I have a feedback form. To receive data from this form, I wrote a node.js code using nodemailer. For nodemailer, it was necessary to create variables stored in the .env file, which is in the same folder as server.ts, but for some reason, when outputting to the console, process.env.NODE_VAR has the value undefined.
.env:
NODE_VAR = value
server.ts:
require('dotenv').config();