NestJS · Middle · Question 75 of 75

What does `@Optional()` on a constructor parameter do?

1It makes the provider lazy
✓Correct answer: If no provider is registered for the token, Nest injects undefined instead of failing
3It marks the parameter as a query parameter

Explanation

Useful for optional integrations, e.g. a module that works with or without a configured metrics client.

Further reading

NestJS: Providers ↗

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