nest-optional-validation-pipes

Nest Optional Validation Pipes

What is this?

This package provides the same validation & transformation pipes as @nestjs/common does, but with optionality.

This means, for example, a ParseBoolOptionalPipe will validate & transform string parameters of the form "true" and "false" into proper booleans true and false but return undefined, if null or undefined is passed as input.

When would I use this?

This is especially useful in the case of optional @Query parameters: Let's say you wanted to add some kind of optional filtering for a resource in your api, so you add a flag as a @Query parameter - using the default ParseBoolPipe will throw an error if the flag is not provided on every request.

This package addresses this exact shortcoming: using a ParseBoolOptionalPipe instead of a ParseBoolPipe will mean the validation will not fail on "no flag provided" - it will return undefined instead, building a bridge.

How do I use this?

Exactly the same way you would use the @nestjs/common Built-in Pipes. See the official nestjs docs for further info.

Credits

Approximately 90% of the code is taken directly from @nestjs/common, I only put my own spin on their already awesome built-in pipes.

So go check them out! (If you don't know them, how did you end up here?)