Configuration

ConfigLoader

@rune/config provides an environment-based configuration loader that auto-parses typed values.

Basic Usage

import { ConfigLoader } from "@rune/config";

const config = new ConfigLoader();

const port = config.get<number>("PORT", 3000);
const dbUrl = config.get<string>("DATABASE_URL");
const debug = config.get<boolean>("DEBUG", false);

Auto-Parsing

Values from process.env are automatically parsed:

Environment Value	Parsed Type
"true"	true
"false"	false
"null"	null
"undefined"	undefined
"8080"	8080 (number)
"hello"	"hello" (string, unmodified)

Exception: the key "PORT" is always stored as a string.

Explicit Set

config.set("DATABASE_URL", "postgres://localhost:5432/myapp");
config.set("MAX_CONNECTIONS", "100"); // stored as number 100
config.set("PORT", "8080"); // stored as string "8080"

Typed Access

const timeout = config.get<number>("REQUEST_TIMEOUT", 5000);
const allowed = config.get<string[]>("ALLOWED_ORIGINS", ["*"]);

With DI

Register the config as a provider:

import { ConfigLoader } from "@rune/config";
import { Module, Injectable } from "@rune/decorators";

@Injectable("singleton")
export class AppConfig {
  readonly port: number;
  readonly dbUrl: string;
  readonly jwtSecret: string;

  constructor() {
    const config = new ConfigLoader();
    this.port = config.get<number>("PORT", 3000);
    this.dbUrl = config.get<string>("DATABASE_URL", "postgres://localhost:5432/app");
    this.jwtSecret = config.get<string>("JWT_SECRET", "dev-secret");
  }
}

With Module

@Module({
  providers: [AppConfig],
  controllers: [UserController],
})
export class AppModule {}

Best Practices

• Prefix env vars with your app name (MYAPP_DB_URL, MYAPP_PORT)
• Use .env files in development (loaded by Bun natively, or via dotenv in Node)
• Never commit secrets. Document required env vars in a .env.example file:

PORT=3000
DATABASE_URL=postgres://localhost:5432/myapp
JWT_SECRET=change-me-in-production