Environment variables in NestJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are environment variables in the context of a NestJS application?

Environment variables are key-value pairs stored outside the code that hold configuration data. They help keep sensitive info like API keys or database URLs separate from the codebase.

beginner

How do you load environment variables in a NestJS app?

You use the @nestjs/config package which reads variables from a .env file and makes them available via ConfigService throughout your app.

beginner

What is the purpose of the ConfigModule in NestJS?

ConfigModule loads environment variables and provides ConfigService to access them safely anywhere in your app.

beginner

How can you access an environment variable called DATABASE_URL inside a NestJS service?

Inject ConfigService and call configService.get('DATABASE_URL') to get the value of DATABASE_URL.

beginner

Why should you avoid hardcoding sensitive data in your NestJS code?

Hardcoding secrets risks exposing them in code repositories. Environment variables keep secrets outside code, improving security and flexibility.

Which NestJS package helps manage environment variables?

A @nestjs/config

B @nestjs/env

C @nestjs/dotenv

D @nestjs/settings

The @nestjs/config package is the official way to load and manage environment variables in NestJS.

Where do you typically store environment variables for a NestJS app?

A Inside the main.ts file

B In the .env file

C In the package.json file

D In the node_modules folder

Environment variables are usually stored in a .env file at the root of the project.

How do you access environment variables inside a NestJS service?

A Using global variables

B Using process.env.VARIABLE_NAME directly

C Using import from dotenv package

D Using ConfigService.get('VARIABLE_NAME')

The recommended way is to inject ConfigService and use its get method to access variables.

What is a key benefit of using environment variables in NestJS?

A Separates config from code for security and flexibility

B Makes the app run faster

C Automatically documents your code

D Prevents all bugs

Environment variables keep sensitive data out of code and allow easy config changes without code edits.

Which method loads environment variables into NestJS at startup?

A process.env.load()

B AppModule.loadEnv()

C ConfigModule.forRoot()

D NestFactory.loadEnv()

Calling ConfigModule.forRoot() in your root module loads environment variables from .env.

Explain how to set up and use environment variables in a NestJS project.

Think about the steps from creating the file to reading variables in services.

Why is it important to use environment variables instead of hardcoding secrets in NestJS?

Consider risks of hardcoding and benefits of separation.