next-typed-env

next-typed-env is a utility that enhances Next.js applications by enabling type-safe handling and validation of environment variables. It generates TypeScript files with typed exports for both client and server environments.

Features

• Validates environment variables against a predefined schema
• Generates TypeScript files with typed exports
• Supports both client and server environments
• Reduces runtime errors by ensuring consistent access to environment variables

Installation

Use npm to install next-typed-env:

npm install next-typed-env

or use yarn:

yarn add next-typed-env

Usage

Define Environment Variables in .env File

Create a .env file in the root directory of your Next.js project and define environment variables:

NEXT_PUBLIC_API_URL=https://api.example.com
SECRET_KEY=mysecretkey
NODE_ENV=development

Define a Schema for Environment Variables

Define a schema for your environment variables using Zod. Use the withTypedEnv function in your Next.js configuration file to integrate next-typed-env.

// next.config.js
import { withTypedEnv } from "next-typed-env";
import { z } from "zod";

const envSchema = z.object({
  NEXT_PUBLIC_API_URL: z.string(),
  SECRET_KEY: z.string(),
  NODE_ENV: z.enum(["development", "production", "test"]),
});

module.exports = withTypedEnv(
  {
    // ...other Next.js config options
  },
  envSchema
);

Generated TypeScript Files

next-typed-env will generate TypeScript files in an /env directory.

// ./env/env.client.ts
export const NEXT_PUBLIC_API_URL = process.env.NEXT_PUBLIC_API_URL as "https://api.example.com";

export const NODE_ENV = process.env.NODE_ENV as "development" | "production" | "test";

Example generated file (env.server.ts):

// ./env/env.server.ts
export const SECRET_KEY = process.env.SECRET_KEY as "mysecretkey";

Use the Generated File in Your Code

Import the environment variables directly from the generated file. This will provide you with type safety:

// example-component.tsx
import { NEXT_PUBLIC_API_URL, NODE_ENV } from "../env/env.client";

console.log(NEXT_PUBLIC_API_URL); // Typed as string

if (NODE_ENV === "production") {
  console.log("You are in production mode.");
} else if (NODE_ENV === "development") {
  console.log("You are in development mode.");
}

// example-server.ts
import { SECRET_KEY } from "../env/env.server";

console.log(SECRET_KEY); // Typed as string

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

License

MIT