Thanks to @bill karvin comment There is no support

https://github.com/prisma/prisma/issues/6336

According to this prisma contributor in this issue

This is works as intended. Purpose of result extensions is to add synchronously computed field to the model with minimum overhead, so it can be queried implicitly

Also the official doc specifies

For performance reasons, Prisma Client computes results on access, not on retrieval.

I've struggles too with this limitation of prisma and my solution was to simply return an async function as the result of the compute method. Then the value can be computed when needed.

const prisma = new PrismaClient().$extends({
  result: {
    user: {
      getNameAndAge: {
        needs: { name: true, age: true },
        compute(user) {
          return async () => (`${user.name} (${user.age}y) ${await getdata()}`)
        },
      },
    },
  },
})

// ...when needed

const joeNameAndAge = await users[0].getNameAndAge()

On the other hand you can define a custom specific for that model that queries and manipulate the data as you need.

You can find more here.

export type UserFindManyWithData = {
  where: Prisma.UserWhereInput
  select: Prisma.UserSelect
}

const prisma = new PrismaClient().$extends({
  model: {
    user: {
      async findManyWithData({ where, select }: UserFindManyWithData) {
        const users = await prisma.user.findMany({ where, select })
                
        // This is not the best strategy for performance, ideally you would like to await all promises at once, but it depends on your project
        for (const user of users) {
          user.nameAndAge = `${user.name} (${user.age}y) ${await getdata()}`
        }
        
        return users
      },
    },
  },
})

You need create field resolver for dynamicPrice field at Item type. It will looks like that:

const resolvers = {
  Query: {
    parsedItem: (parent, args, ctx, info) => {
      ...
    }
    ...
  },
  Item: {
    dynamicPrice: parent => parent.basePrice + parent.addons.length * 5
  }
}

More details you can find at A Guide to Common Resolver Patterns.

HI @tithanayut 👋

Thank you for raising this question.

Prisma does not yet natively support computed fields in the type system. The computed fields are added to the result object and are not part of the Prisma-generated types like Prisma.UserGetPayload. We use Prisma Client extensions as a way to add computed fields at runtime. To see this specific support, can you please add your usecase to this open issue.

If this answers your question, it would be great if you could mark this Discussion as answered to indicate that it has been resolved.

Otherwise please let us know how else we can help you further or close the Discussion if it was resolved in some other way 🙏