ConfigModule setup in NestJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the ConfigModule in NestJS?

The ConfigModule helps manage application configuration settings in a centralized and organized way, allowing easy access to environment variables and config values throughout the app.

beginner

How do you import the ConfigModule globally in a NestJS application?

Use ConfigModule.forRoot({ isGlobal: true }) in the root module's imports array. This makes the configuration available in all modules without needing to import ConfigModule again.

beginner

What file does ConfigModule load by default when using forRoot()?

By default, ConfigModule loads the .env file from the project root to read environment variables.

intermediate

How can you validate environment variables when setting up ConfigModule?

You can pass a validationSchema option with a Joi schema to ConfigModule.forRoot() to check environment variables and ensure they meet expected formats.

beginner

How do you access a configuration value inside a service after setting up ConfigModule?

Inject ConfigService in the service constructor, then use configService.get('KEY_NAME') to get the value of a config key.

Which method makes ConfigModule available globally in NestJS?

A ConfigModule.forRoot({ isGlobal: true })

B ConfigModule.forFeature()

C ConfigModule.register()

D ConfigModule.useGlobal()

Using forRoot with isGlobal: true makes ConfigModule available across all modules without re-importing.

What file does ConfigModule load by default to get environment variables?

A settings.yaml

B config.json

C .env

D package.json

ConfigModule loads the .env file by default to read environment variables.

How do you access a config value inside a NestJS service?

A Inject ConfigService and call get('KEY')

B Use process.env.KEY directly

C Import ConfigModule inside the service

D Call ConfigModule.getConfig('KEY')

Injecting ConfigService and calling get('KEY') is the recommended way to access config values.

Which package is commonly used to validate environment variables in ConfigModule?

A Lodash

B Joi

C Express

D Axios

Joi is a popular validation library used to define schemas for environment variables.

What happens if you don't set isGlobal: true in ConfigModule.forRoot()?

A Application will crash

B ConfigModule will not load .env file

C ConfigService will be unavailable

D You must import ConfigModule in every module that needs it

Without isGlobal: true, you need to import ConfigModule in each module that uses it.

Explain how to set up ConfigModule globally in a NestJS app and why it is useful.

Think about how to avoid importing ConfigModule repeatedly.

Describe how to validate environment variables using ConfigModule in NestJS.

Validation helps catch config errors early.