I want to modify data from a prisma query before users receive the data through the various

prisma.modelName.queryName

methods - but after the query successfully complets. As a contrived example, let’s say I have a model like this:

model Person {
   id @id @default(cuid())

   first_name String
   
   gender Gender
}

Now what if I want to modify

first_name

after fetching it from the database to include

Mr

or

Ms

. so that if i do:

const bob = await prisma.person.findFirst({
  where: { id: someCuid }
})

Then

bob.first_name

should say

Mr. bob

or something like that. I know that Prisma has middleware using

prisma.$use

but I don’t quite understand how i’d go about doing this since this is a post-query modification … as opposed to a pre-query modification that I see examples of in the docs

Why do you want to do this in Prisma? This seems like a processing step to be done after, by just setting:

bob.first_name = `${bob.gender}. ${bob.first_name}`;

This seems like a more straighforward solution, especially if you're using a common interface (i.e. a UserService) to access the model. However, i've not actually done this but afaik, you do it in the same middleware. Anything you put before

await next(params);

happens before the query, and any code after that is once the query has returned. So you should be able to do something like this in your middleware:

const res = await next(params);
return {
    ...res,
    first_name: `${res.gender}. ${res.first_name}`
}

In the middleware, you just do it after calling

next

which executes the query.

Thank you both!