getenv.ts

getenv.ts

Helper to get, validate, cast and provide type safety for environment variables with TypeScript.

Installation

pnpm add getenv.ts
# or
npm install getenv.ts

Usage

Set environment variables in a suitable file, and load them in using a library like dotenv/dotenv-safe, or similar strategy:

export HTTP_HOST="localhost"
export HTTP_PORT=8080
export HTTP_SECURE=true
export AB_TEST_RATIO=0.5

Alternatively, pass the variables along with the execution command:

HTTP_HOST="localhost" HTTP_PORT=8080 node main.ts

Basically, all variables you intend to use must be loaded into process.env in order to be available for getting.

Then you just have to import the package and use the variables:

import getenv from "getenv.ts";

// Get values cast to desired type.
const host: string = getenv.string("HTTP_HOST");
const port: number = getenv.int("HTTP_PORT");
const secure: boolean = getenv.bool("HTTP_SECURE");
const abTestRatio: number = getenv.float("AB_TEST_RATIO");

// Use default value if variable isn't defined.
const sudoUser = getenv.string("SUDO_USER", "root");

// Throws `ReferenceError` when variable isn't defined.
try {
	const invalid = getenv.string("DOES_NOT_EXIST");
} catch (error) {
	// Will throw...
}

// Throws `TypeError` when variable isn't of the expected type.
try {
	const invalid = getenv.int("HTTP_HOST");
} catch (error) {
	// Will throw...
}