Dotenv Module

The std/dotenv module loads environment variables from .env files and provides runtime access to environment variables.

Import

import { dotenv } from "std/dotenv"

Functions

dotenv.load(path?: string): bool

Load environment variables from a .env file. Defaults to ".env" in the current directory. Returns true on success.

dotenv.load()               // Load from .env
dotenv.load(".env.local")   // Load from a specific file

dotenv.get(key: string, defaultValue?: string): string

Get an environment variable by key. Returns the value, the default, or null if not found.

const port = dotenv.get("PORT", "3000")
const dbUrl = dotenv.get("DATABASE_URL")

dotenv.set(key: string, value: string): void

Set an environment variable at runtime.

dotenv.set("NODE_ENV", "production")

dotenv.has(key: string): bool

Check if an environment variable exists.

if (dotenv.has("API_KEY")) {
    println("API key configured")
}

dotenv.all(): map

Get all loaded environment variables as a map.

const env = dotenv.all()
for (var key in env) {
    println(key + "=" + env[key])
}

dotenv.require(key: string): string

Get a required environment variable. Throws an Error if the variable is not set.

try {
    const secret = dotenv.require("JWT_SECRET")
} catch (err) {
    println("Missing required config: " + err.message)
}

Function Reference

Function	Description
dotenv.load(path?)	Load variables from .env file
dotenv.get(key, default?)	Get a variable (with optional default)
dotenv.set(key, value)	Set a variable at runtime
dotenv.has(key)	Check if a variable exists
dotenv.all()	Get all variables as a map
dotenv.require(key)	Get a required variable (throws if missing)

Example: Server Configuration

import { dotenv } from "std/dotenv"
import { createServer, Request, Response } from "std/http"

// Load environment variables
dotenv.load()

const port = int(dotenv.get("PORT", "3000"))
const secret = dotenv.require("JWT_SECRET")

const app = createServer()

app.get("/health", function(req: Request, res: Response): Response {
    return res.json('{"status": "ok"}')
})

app.listen(port)

.env File Format

# Comments start with #
PORT=3000
DATABASE_URL=postgres://localhost/mydb
JWT_SECRET=my-super-secret-key
DEBUG=true