ENV validation library

This library is designed to support validating environment variables for a nodejs application of any kind.

How to use

In a file (e.g. config.js)

require('dotenv').config();

const {validate, validations, preProcessors} = require('@learningalbum/env-validation');

const {castBool} = preProcessors;
const {mustBeOneOf, requiredIfPresent, requiredIfTrue} = validations;

const varsConfig = [
  // Array of variable configs (see below)
  {
    name: 'MY_VAR',
    require: true,
  }
]

// Get the validated vars into an object like {VAR1, VAR2, VAR3, etc} 
module.exports = validate(varsConfig);

Then in your application code, wherever you need config from your env, you do stuff like:

const { MY_VAR } = require('config.js');
// Do something with MY_VAR

or, if using ESM:

import envs from './config.js';
const { MY_VAR } = envs;

If MY_VAR doesn't validate in the way you've configured in config.js, an error will be thrown with an error message describing why.

Variable configs

Declare each variable you want to validate. For full details on the interface, please see src/types.ts.

key	type	required?	description
name	string	yes	the name of the variable to pick up from process.env
default	any	no	a default value to use
preProcess	(val: any) => any	no	function to transform the value before any validation
validations	array of (val: any, context?: EnvContext) => boolean	no	function to validate the value
deprecated	boolean	no	whether this var is marked as deprecated
message	string	no	the deprecation message to show if the deprecated var is present (only relevant when deprecated: true)