Handles environment variables in Javascript or Typescript

Of course, one thing we always do when creating a JavaScript, Node.js, Bun, etc. project is to handle environment variables. To do this, we create an .env file and read it with process.env. However, this can be a bit tedious, validating that all variables exist, that they have a default value, etc.

Requirements

• The first thing is to have a JavaScript, Node.js, Bun, etc. project.
• Install the zod library.

Steps

1. Install the zod library

npm install zod       # npm
yarn add zod          # yarn
bun add zod           # bun
pnpm add zod          # pnpm

2. Create a .env file with the environment variables

PORT=3000
DB_HOST=

3. Create an env.ts or env.js file with the following content

const z = require("zod");

const envSchema = z.object({
  PORT: z.string().default("3000"),
  DB_HOST: z.string().default("localhost"),
});

const env = envSchema.parse(process.env);

module.exports = env;

import { z } from "zod";

const envSchema = z.object({
  PORT: z.string().default("3000"),
  DB_HOST: z.string().default("localhost"),
});

// If you need Bun you can change the process.env to Bun.env
export const env = envSchema.parse(process.env);

Thanks to zod, we can validate that environment variables exist and have a default value. If they do not exist, the default value will be used. We can also say that they are optional with z.string().optional(). or that they have a minimum number of characters with z.string().min(3).

4. Using environment variables

const env = require("./env.js");

console.log(env.PORT); // "3000"
console.log(env.DB_HOST); // "localhost"

import { env } from "./env";

console.log(env.PORT); // "3000"
console.log(env.DB_HOST); // "localhost"

In this way, we can manage environment variables easily and safely.