Managing application configuration is crucial for security and flexibility, such as storing API keys, database credentials, or various settings. Using Environment Variables is the best practice for managing configuration without hardcoding sensitive information. In this article, we will show how to use environment variables and configuration management in Go and Node.js, with practical code examples and best practices.

1. Environment Variables in Node.js

Node.js can access environment variables through process.env.

Example: Reading an environment variable

// Assuming the terminal sets the environment variable
// export PORT=3000

const port = process.env.PORT || 8080;
console.log(`Server will run on port: ${port}`);

Using .env file with dotenv

// Install dotenv
// npm install dotenv

require('dotenv').config();

const port = process.env.PORT || 8080;
const dbUser = process.env.DB_USER;
const dbPassword = process.env.DB_PASSWORD;

console.log(`Connecting to DB as ${dbUser}`);

Advantages of Node.js Environment Variables
✔️ Easy access via process.env
✔️ Convenient usage with .env files and libraries like dotenv
✔️ Supports multiple environments: development, staging, production

Cautions
⚠️ Never commit .env files to the repository
⚠️ Set default values for critical environment variables

2. Environment Variables in Go

Go can access environment variables via the os package.

Example: Reading an environment variable

package main

import (
    "fmt"
    "os"
)

func main() {
    port := os.Getenv("PORT")
    if port == "" {
        port = "8080"
    }
    fmt.Println("Server will run on port:", port)
}

Using configuration files and environment variables

import (
    "fmt"
    "github.com/joho/godotenv"
    "os"
)

func main() {
    err := godotenv.Load(".env")
    if err != nil {
        fmt.Println("Error loading .env file")
    }

    dbUser := os.Getenv("DB_USER")
    dbPassword := os.Getenv("DB_PASSWORD")
    fmt.Printf("Connecting to DB as %s\n", dbUser)
}

Advantages of Go Environment Variables
✔️ Type-safe when converting values to integer, boolean, etc.
✔️ Works well with system environment variables
✔️ Supports multiple environments via .env files or config structs

Cautions
⚠️ Convert environment variable values carefully to the correct type
⚠️ Never store credentials directly in the code

3. Best Practices

✔️ Store sensitive values like API keys, passwords, and DB credentials in environment variables
✔️ Set default values for critical variables to avoid errors
✔️ Use configuration management libraries:

• Node.js: dotenv, convict
• Go: godotenv, viper
  ✔️ Separate configuration by environment (development, staging, production)
  ✔️ Do not commit .env or other secret files to the repository

4. Comparison: Go vs Node.js

Recommendations
✔️ For frontend / backend web apps → Use Node.js + dotenv
✔️ For backend services / CLI / server → Use Go + godotenv or viper

Next Episode

In EP.27 of JS2GO, we will learn about Logging: JavaScript vs Go to build an efficient event logging system and track issues in production professionally.

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