envguard-checker

A simple and lightweight environment variable checker for Node.js applications.

envguard-checker helps you make sure that all required environment variables are available before your application starts.

Installation

npm install envguard-checker

If you are using a .env file, install dotenv as well:

npm install dotenv

Usage

CommonJS

require("dotenv").config();

const { checkEnv } = require("envguard-checker");

checkEnv({
  required: ["DATABASE_URL", "JWT_SECRET"],
  optional: ["REDIS_URL", "PORT"]
});

console.log("Environment variables are valid!");

ES Modules

import "dotenv/config";
import { checkEnv } from "envguard-checker";

checkEnv({
  required: ["DATABASE_URL", "JWT_SECRET"],
  optional: ["REDIS_URL", "PORT"]
});

console.log("Environment variables are valid!");

TypeScript

import "dotenv/config";
import { checkEnv } from "envguard-checker";

checkEnv({
  required: ["DATABASE_URL", "JWT_SECRET"],
  optional: ["REDIS_URL", "PORT"]
});

console.log("Environment variables are valid!");

Environment Variables

Example .env file:

DATABASE_URL=postgresql://localhost/mydb
JWT_SECRET=my-secret
PORT=3000
REDIS_URL=redis://localhost:6379

Required Variables

Variables inside required must exist.

checkEnv({
  required: ["DATABASE_URL", "JWT_SECRET"]
});

If a required variable is missing, envguard-checker throws an error:

Error: Missing Environment variables: JWT_SECRET

Multiple missing variables are reported together:

Error: Missing Environment variables: DATABASE_URL, JWT_SECRET

Optional Variables

Variables inside optional do not have to exist.

checkEnv({
  required: ["DATABASE_URL"],
  optional: ["REDIS_URL", "PORT"]
});

If REDIS_URL or PORT is missing, no error is thrown.

Currently, optional is used to document which environment variables are optional. Missing optional variables do not cause validation errors.

API

checkEnv(options)

checkEnv({
  required?: string[],
  optional?: string[]
});

Options

| Option | Type | Description | | ---------- | ---------- | ---------------------------------------------------- | | required | string[] | Environment variables that must exist | | optional | string[] | Environment variables that are allowed to be missing |

Return Value

Returns:

true

when all required environment variables are available.

Error

Throws an error when one or more required environment variables are missing.

Example:

Error: Missing Environment variables: DATABASE_URL, JWT_SECRET

Example

require("dotenv").config();

const { checkEnv } = require("envguard-checker");

checkEnv({
  required: [
    "DATABASE_URL",
    "JWT_SECRET"
  ],
  optional: [
    "PORT",
    "REDIS_URL"
  ]
});

console.log("Application starting...");

TypeScript Support

envguard-checker includes TypeScript type definitions.

This means TypeScript can detect invalid usage:

checkEnv({
  required: "DATABASE_URL"
});

TypeScript will report:

Type 'string' is not assignable to type 'string[]'.

Correct usage:

checkEnv({
  required: ["DATABASE_URL"]
});

License

MIT

Author

Muhammad Saifullah