Custom providers in NestJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a custom provider token.

NestJS

const MY_SERVICE = '[1]';

Drag options to blanks, or click blank then click option'

AMyServiceToken

BmyService

CSERVICE

DCustomProvider

Attempts:

3 left

💡 Hint

Common Mistakes

Using a generic string like 'SERVICE' which may cause conflicts.

Using variable names instead of string tokens.

The token MyServiceToken is a common pattern to identify a custom provider uniquely.

2fill in blank

medium

Complete the code to provide a custom class provider in NestJS.

NestJS

providers: [{ provide: MY_SERVICE, use[1]: MyServiceClass }]

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Aclass

Bvalue

CClass

Dfactory

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'usevalue' or 'usevalue' instead of 'useClass'.

Confusing 'useFactory' with 'useClass'.

The useClass key tells NestJS to use the given class as the provider implementation.

3fill in blank

hard

Fix the error in the custom provider definition by completing the blank.

NestJS

providers: [{ provide: MY_SERVICE, use[1]: () => new MyService() }]

Drag options to blanks, or click blank then click option'

AFactory

BFactoryFunction

CValue

DClass

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'useClass' with a function instead of a class.

Using 'useValue' with a function instead of a value.

When providing a factory function, the correct key is useFactory.

4fill in blank

hard

Fill both blanks to create a custom provider that uses a value.

NestJS

providers: [{ provide: [1], use[2]: { name: 'Test' } }]

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AMY_SERVICE

BValue

CuseClass

DMY_VALUE

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'useClass' when providing a value object.

Using an undefined token name.

Use MY_SERVICE as the token and useValue to provide a fixed value.

5fill in blank

hard

Fill all three blanks to create a factory provider with dependencies.

NestJS

providers: [{ provide: [1], use[2]: (dep) => new MyService(dep), inject: [[3]] }]

Drag options to blanks, or click blank then click option'

AMY_SERVICE

BFactory

CDependencyService

DuseFactory

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'useClass' instead of 'useFactory' for factory providers.

Not listing dependencies in the inject array.

Using wrong token names.

The token is MY_SERVICE, the key for factory is useFactory, and the dependency injected is DependencyService.