Prisma•5mo ago

Incorrect type being returned from getQueryMethod

type ModelName = Prisma.ModelName;
type ModelDelegate<N extends ModelName> = PrismaClient[Uncapitalize<N>];

export function getQueryMethod<T extends ModelDelegate<ModelName>>(model: T, single: boolean = false) {
  const method = single ? 'findFirst' : 'findMany';
  return model[method];
}

export class ClusterRepository implements IClusterRepository {
  constructor(private readonly databaseClientService: IDatabaseClientService) {}
  

  async getClustersByCriteria(criteria: Prisma.ClusterWhereInput, options: QueryOptions) {
    return withDatabaseError(async () => {
      const refinedClient = getQueryMethod(this.databaseClientService.cluster, options.single);
      return refinedClient({ where: criteria, ...options });
    });
  }

type ModelName = Prisma.ModelName;
type ModelDelegate<N extends ModelName> = PrismaClient[Uncapitalize<N>];

export function getQueryMethod<T extends ModelDelegate<ModelName>>(model: T, single: boolean = false) {
  const method = single ? 'findFirst' : 'findMany';
  return model[method];
}

export class ClusterRepository implements IClusterRepository {
  constructor(private readonly databaseClientService: IDatabaseClientService) {}
  

  async getClustersByCriteria(criteria: Prisma.ClusterWhereInput, options: QueryOptions) {
    return withDatabaseError(async () => {
      const refinedClient = getQueryMethod(this.databaseClientService.cluster, options.single);
      return refinedClient({ where: criteria, ...options });
    });
  }

refinedClient is giving me this: 'This expression is not callable. Each member of the union type '(<T extends AgentFindFirstArgs>(args?: SelectSubset<T, AgentFindFirstArgs<DefaultArgs>> | undefined) => Prisma__AgentClient<GetFindResult<$AgentPayload<DefaultArgs>, T, PrismaClientOptions> | null, null, DefaultArgs, PrismaClientOptions>) | ... 76 more ... | (<T extends UserFindManyArgs>(args?: SelectSubset<...> | u...' has signatures, but none of those signatures are compatible with each other.ts(2349)'

4 Replies

Prisma AI Help•5mo ago

You selected the bot's instantaneous insights. Let me compile your answer right away! The error you're seeing is a well-known TypeScript limitation when trying to call a method on a union of Prisma model delegates. When you use a generic like ModelDelegate<N extends ModelName> = PrismaClient[Uncapitalize<N>], the resulting type is a union of all possible model delegates. Each delegate has its own method signatures, and TypeScript cannot guarantee that the method signatures are compatible, so it prevents you from calling the method directly. This leads to the "Each member of the union type ... has signatures, but none of those signatures are compatible with each other" error. This is discussed in several issues and comments: - The root cause is that TypeScript cannot safely call a method on a union of types with incompatible signatures, which is exactly what happens when you try to access model[method] in your getQueryMethod function. Even if all delegates have a findMany or findFirst, their argument types differ, so TypeScript cannot resolve the call safely. This is why you get the error when using a variable of type PrismaClient[Uncapitalize<N>] where N is a union of model names, or when you try to use a generic function to abstract over models in this way No easy way to get prisma client table names in typescript. - Workarounds include using type assertions (as any), or narrowing the type with an if statement to a specific model name before calling the method, as mentioned in the comments. For example, you can check if the model is a specific delegate before calling the method, which allows TypeScript to infer the correct type No easy way to get prisma client table names in typescript. - There is currently no official, type-safe way to generically call model methods across all models without running into this TypeScript limitation. This is a known pain point in the Prisma community [No easy way to get prisma client table names in typescript](<h ttps://github.com/prisma/prisma/issues/11940>). In summary: This is a TypeScript limitation with union types and method signatures in Prisma. The only workarounds are type assertions or explicit type narrowing. There is no fully type-safe, generic solution available in Prisma at this time.

Nurul•5mo ago

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Prisma AI Help•5mo ago

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Nurul•5mo ago

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Incorrect type being returned from getQueryMethod

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