ConfigJS is a robust and 100% type-safe configuration management system for Node.js and Bun applications. It provides a structured way to define, validate, and access environment variables and other configuration sources with the power of TypeScript.

• ✅ Fully Typed: Autocomplete and type safety for all your configurations.
• ✅ Flexible Drivers: Load configurations from .env files, JSON, or create your own driver.
• ✅ Built-in Validation: Define rules and formats (email, url, etc.) directly in the schema.
• ✅ Smart Defaults: Define defaults that are applied automatically.
• ✅ Nested Structures: Organize your configurations logically.

• Full Usage Guide: Learn how to install and use ConfigJS.
• Schema Definitions: See all available validators and options.
• Creating Drivers: Learn how to load configurations from any source.

npm install @caeljs/config
# or
yarn add @caeljs/config
# or
bun add @caeljs/config

1. Define your schema (schema.ts):

import { c } from "@caeljs/config";

export const AppSchema = {
  server: {
    host: c.string({ default: "0.0.0.0" }),
    port: c.number({ default: 3000 }),
  },
  database: {
    url: c.string({ prop: "DATABASE_URL" }), // Reads from the DATABASE_URL environment variable
  },
};

2. Create and load your instance (config.ts):

import { ConfigJS } from "@caeljs/config";
import { envDriver } from "@caeljs/config/drivers";
import { AppSchema } from "./schema";

const config = new ConfigJS(envDriver, AppSchema);
config.load(); // Loads values from .env and process.env

export default config;

3. Use it anywhere (index.ts):

import config from "./config";

const port = config.get("server.port"); // Inferred as `number`
const dbUrl = config.get("database.url"); // Inferred as `string`

console.log(`Server running on port ${port}`);

// Type Error! TypeScript prevents incorrect assignments.
// config.set("server.port", "not-a-number");

MIT