load environment file like nextjs, it can load multiple .env file and can replace in multiple stage

load-env.deno.ts

// Deno

import { loadSync } from "jsr:@std/dotenv";
import { log } from "./logging.ts";

const loadMatrix = async (paths: string[]): Promise<Record<string, string>> => {
  let result: Record<string, string> = {};
  const loadedFrom: string[] = [];

  for (const path of paths) {
    const res = loadSync({
      envPath: path,
    });

    if (Object.keys(res).length > 0) {
      loadedFrom.push(path);
    }

    result = {
      ...result,
      ...res,
    };
  }

  for (const [key, value] of Object.entries(result)) {
    Deno.env.set(key, value);
  }

  log.info(`Loaded env from: ${loadedFrom.join(", ")}`);

  return result;
};

await loadMatrix([".env", ".env.local", ".env.production.local"]);

// then import on `main.ts` file
// import "load-env.deno.ts";

load-env.js

// Node Javascript

import { configDotenv } from 'dotenv'

const loadMatrix = async (paths) => {
    let result = {}
    const loadedFrom = []

    for (const path of paths) {
        const res = configDotenv({
            debug: true,
            path: path,
            encoding: 'utf-8',
        })

        if (!res.error) {
            loadedFrom.push(path)
        }

        result = {
            ...result,
            ...res,
        }
    }

    console.info(`Loaded env from: ${loadedFrom.join(', ')}`)

    return result
}

await loadMatrix(['.env', '.env.local', '.env.production.local'])

// then import on `index.js` file
// import "load-env.js"

load-env.ts

// Node Typescript

import { configDotenv } from 'dotenv';

const loadMatrix = async (paths: string[]): Promise<Record<string, string>>  => {
    let result: Record<string, string> = {};
    const loadedFrom: string[] = [];

    for (const path of paths) {
        const res = configDotenv({
            debug: true,
            path: path,
            encoding: 'utf-8',
        });

        if (!res.error) {
            loadedFrom.push(path);
        };

        result = {
            ...result,
            ...res,
        };
    }

    console.info(`Loaded env from: ${loadedFrom.join(', ')}`);

    return result;
}

await loadMatrix(['.env', '.env.local', '.env.production.local'])

// then import on `index.ts` file
// import "load-env.ts"