getEnv

The getEnv function retrieves environment variables with validation. It throws an exception if any requested variables are missing, ensuring your application fails fast with clear error messages.

An in Depth Example

This guide also has an in depth example of a working application built with EventFabric. Combining DDD, CQRS and Event Sourcing.

Check out the In Depth Example page to learn how everything is connected and works out in a real-world application.

Basic Usage

import { getEnv } from "@nimbus-cqrs/utils";

const env = getEnv({
    variables: ["DATABASE_URL", "API_KEY", "PORT"],
});

console.log(env.PORT);

Function Signature

getEnv({ variables: string[] }): Record<string, string>

Parameter	Type	Description
variables	string[]	Array of environment variable names

Returns	Description
Record<string, string>	Object with variable names as keys and values

Error Handling

If any requested variables are undefined, getEnv throws a GenericException with details about all missing variables:

import { getEnv } from "@nimbus-cqrs/utils";

try {
    const env = getEnv({
        variables: ["MISSING_VAR_1", "MISSING_VAR_2"],
    });
} catch (error) {
    // GenericException with:
    // - message: "Undefined environment variables"
    // - details: { undefinedVariables: ["MISSING_VAR_1", "MISSING_VAR_2"] }
}

The error is also logged before throwing:

[Nimbus] ERROR :: Undefined environment variables
{ undefinedVariables: ["MISSING_VAR_1", "MISSING_VAR_2"] }

Use Cases

Application Configuration

import { getEnv } from "@nimbus-cqrs/utils";

const env = getEnv({
    variables: ["NODE_ENV", "PORT", "DATABASE_URL", "REDIS_URL", "JWT_SECRET"],
});

export const config = {
    nodeEnv: env.NODE_ENV,
    port: parseInt(env.PORT, 10),
    databaseUrl: env.DATABASE_URL,
    redisUrl: env.REDIS_URL,
    jwtSecret: env.JWT_SECRET,
};

MongoDB Connection

import { MongoConnectionManager } from "@nimbus-cqrs/mongodb";
import { getEnv } from "@nimbus-cqrs/utils";

const env = getEnv({
    variables: ["MONGO_URL", "MONGO_DB"],
});

const mongoManager = MongoConnectionManager.getInstance(env.MONGO_URL, {
    mongoClientOptions: { appName: "my-app" },
});

export const getCollection = (name: string) =>
    mongoManager.getCollection(env.MONGO_DB, name);

Repository Configuration

import { MongoDBRepository } from "@nimbus-cqrs/mongodb";
import { getEnv } from "@nimbus-cqrs/utils";
import { mongoManager } from "./mongodb.ts";

class UserRepository extends MongoDBRepository<User> {
    constructor() {
        const env = getEnv({ variables: ["MONGO_DB"] });

        super(
            () => mongoManager.getCollection(env.MONGO_DB, "users"),
            UserSchema,
            "User"
        );
    }
}

External Service Configuration

import { getEnv } from "@nimbus-cqrs/utils";

const env = getEnv({
    variables: ["STRIPE_API_KEY", "STRIPE_WEBHOOK_SECRET"],
});

export const stripeClient = new Stripe(env.STRIPE_API_KEY);
export const webhookSecret = env.STRIPE_WEBHOOK_SECRET;