@skyra/env-utilities

Functional utilities for reading and parsing environmental variables, based on Skyra's internal tools.

Usage

Setup

To setup @skyra/env-utilities, you use the setup function exported by the package:

import { setup } from '@skyra/env-utilities';

// Set the path as the `.env` file besides the current module:
// NOTE: If not set, it defaults to dotenv's default, `path.resolve(process.cwd(), '.env')`.
setup(new URL('.env', import.meta.url));

You can also pass a string or if you want to define other options, you may use EnvSetupOptions. Optionally, you may configure dotenv via environment variables:

• DOTENV_DEBUG: configures EnvSetupOptions.debug. If enabled, the library will log to help debug why certain keys or values are not being set as expected.
• DOTENV_ENCODING: configures EnvSetupOptions.encoding. If set, it will specify the encoding of the files containing the environment variables
• DOTENV_ENV: configures EnvSetupOptions.env. If set, it will specify a custon environment if NODE_ENV is not sufficient.
• DOTENV_PATH: configures EnvSetupOptions.path. If set, it will specify a custom path to the file containing environment variables, useful for when they are located elsewhere.
• DOTENV_PREFIX: configures EnvSetupOptions.prefix. If set, it will specify a required prefix for dotenv variables (e.g. APP_).

What .env files can be used?

• .env: Default.
• .env.local: Local overrides. This file is loaded for all environments except test.
• .env.development, .env.test, .env.production: Environment-specific settings.
• .env.development.local, .env.test.local, .env.production.local: Local overrides of environment-specific settings.

Files on the left have more priority than files on the right:

• npm start: .env.development.local, .env.local, .env.development, .env
• npm test: .env.test.local, .env.test, .env (note .env.local is missing)

CRA Reference

Typing Environment Variables

To add new entries, you augment Env from @skyra/env-utilities/dist/lib/types using any of the following types:

• BooleanString: can be parsed with envParseBoolean.
• IntegerString: can be parsed with envParseInteger.
• NumberString: can be parsed with envParseNumber.
• string: can be parsed with envParseString and envParseArray.

The above 5 functions will throw an ReferenceError instance if a key is missing (unless a default is passed in the second parameter) as well as a TypeError instance if a key could not be parsed. The default value is returned as-is and is not validated.

An example of adding more keys is as it follows:

import type { BooleanString, IntegerString, NumberString } from '@skyra/env-utilities';

declare module '@skyra/env-utilities' {
	interface Env {
		// Accepts 'true' or 'false':
		ENABLE_TELEMETRY: BooleanString;

		// Accepts any integer, e.g. '10':
		REFRESH_INTERVAL: IntegerString;

		// Accepts any number, e.g. '1.5':
		MINIMUM_SPEED: NumberString;

		// Accepts any string:
		APPLICATION_SECRET: string;
	}
}