Simple question: changing types on the way out

[ajoslin]

Hi, first - LOVE pothos + prisma. We are using it extensively. ❤️ Thank you @hayes.

Question: In pothos, often we query a relation in a way that we want a boolean. For example, we have a User prisma atype and I want to add a field isSelfFollowing that checks if the logged in user making the query is following the User being queried.

To do this, I set up a relation('followers') and add context.userId to the query for that relation. This ends up returning an array of followers, which is kind of a cumbersome way for the API to express whether or not self is following the queried User.

Is there a way to get Pothos to create these optimal joined Prisma queries, as relation+query:()=>{} does, THEN on the way out map something like this to a boolean?

[hayes]

You could do something like this:

builder.prismaObject('Post', {
  fields: (t) => ({
    id: t.exposeID('id'),
    title: t.exposeString('title'),
    content: t.exposeString('content'),
    author: t.relation('author'),
    comments: t.relation('comments'),
    hasCommented: t.boolean({
      select: (args, ctx) => ({
        comments: {
          where: {
            author: {
              id: ctx.user!.id,
            },
          },
          take: 1,
          // only load the id (optional)
          select: {
            id: true,
          },
        },
      }),
      resolve: (post) => post.comments.length > 0,
    }),
  }),
});