Prisma•5mo ago

Adding fields to a templated `select`

Hi, Let's say I have a getUser function, which takes a select as its argument :

const getUser = async <T extends Prisma.UserSelect>(select: T) => {
  return await prisma.user.findFirst({select})
}

const getUser = async <T extends Prisma.UserSelect>(select: T) => {
  return await prisma.user.findFirst({select})
}

Now I want to add a log that says which user I'm getting, so I try this :

const getUser = async <T extends Prisma.UserSelect>(select: T) => {
  const user = await prisma.user.findFirst({
    select: {...select, id: true},
  })
  console.log(`Getting user ${user.id}`)
  return user
}

const getUser = async <T extends Prisma.UserSelect>(select: T) => {
  const user = await prisma.user.findFirst({
    select: {...select, id: true},
  })
  console.log(`Getting user ${user.id}`)
  return user
}

But now I have the following TypeScript error:

Type 'T & { id: true; }' is not assignable to type 'T & { id: true; }'. Two different types with this name exist, but they are unrelated.

So I found the workaround of creating a variable for the select :

const getUser = async <T extends Prisma.UserSelect>(select: T) => {
  const selectWithId = {...select, id: true}
  const user = await prisma.user.findFirst({select: selectWithId})
  console.log(`Getting user ${user.id}`)
  return user
}

const getUser = async <T extends Prisma.UserSelect>(select: T) => {
  const selectWithId = {...select, id: true}
  const user = await prisma.user.findFirst({select: selectWithId})
  console.log(`Getting user ${user.id}`)
  return user
}

That gets rid of the previous error, but I still have an error on the user.id : Property 'id' does not exist on type GIANT_TYPESCRIPT_TYPE. Is there a workaround for this? Adding fields to a templated select is a use-case that came up a few times already in my codebase so I'm trying to find a proper solution (right now we just slap an any on there). Thank you

3 Replies

moosthuizen•5mo ago

@Baptiste Marchand I'm trying to recreate, but no errors on my side:

const selectFirstSite = async <T extends Prisma.MSiteSelect>(select: T) => {
    const select2 = { ...select, id: true };
    const site = await db.mSite.findFirst({
        select: select2,
    });
    console.log(site);
    return site;
};

const selectFirstSite = async <T extends Prisma.MSiteSelect>(select: T) => {
    const select2 = { ...select, id: true };
    const site = await db.mSite.findFirst({
        select: select2,
    });
    console.log(site);
    return site;
};

Baptiste Marchand•5mo ago

@moosthuizen Can you do console.log(site.id) instead ? That's the part that is breaking for me

moosthuizen•5mo ago

Ahh, I'm with you. Will try later and let you know if I figure it out

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Adding fields to a templated `select`