prisma.ts

declare global {
    var prisma: PrismaClient; // This must be a `var` and not a `let / const`
  }

import { PrismaClient } from '@prisma/client'
 let prisma: PrismaClient;
 if(process.env.NODE_ENV === 'production'){
    prisma = new PrismaClient();
}
 else{
    if(!global.prisma){
        global.prisma = new PrismaClient();
    }
    prisma = global.prisma
}  
 
export default prisma;  




graphl.ts

import { createServer , createPubSub } from '@graphql-yoga/node'
import { User } from '@prisma/client'
import type { NextApiRequest, NextApiResponse } from 'next'
import prisma from '../../lib/prisma'

const schema = {schema: {
    typeDefs: /* GraphQL */ `
    
      type User {
        lname: String
        fname: String
     }
   
    type Mutation{
      addUser(lname: String, fname: String): User!
    }
    `,
    resolvers: {
    
         Mutation: {
         addUser: async(parent: any,_: any) => {
           return await prisma.user.create(
            data:{
              lname:"coucou",
              fname:"salut"
            }
       )}  

    },
    
  }
}

i just want to add a new user in graphql with prisma but the resolver don't work                  <https://github.com/doddynicolas/try-prisma.git>