CODEWITHSUNDEEP
typescriptnestjsprisma
Shiladitya Thakur
Shiladitya Thakur

Reputation: 330

how to tell typescript that given input would have a subset of expected type

I am using nestjs with prisma and after migrating the schema.prisma, many Prisma types got automatically generated. I am not sure about what exactly is the correct way to use the generated types but I am using the generated types on service file and my own Dto for controller for validations. However, this is giving problems like:

Type 'number | IntFieldUpdateOperationsInput' is not assignable to type 'number'. Type 'IntFieldUpdateOperationsInput' is not assignable to type 'number'.

this type IntFieldUpdateOperationsInput was autogenerated by prisma for the @default(autoincrement()). However, I don't think I even need this for my use case as only number type for id would suffice.

  export type IntFieldUpdateOperationsInput = {
    set?: number
    increment?: number
    decrement?: number
    multiply?: number
    divide?: number
  }

category.service.ts

  ...
  update({ id, name }: Prisma.MainCategoryUncheckedUpdateInput) {
    return this.prismaService.mainCategory.update({
      where: { id },
      data: { name },
    });
  }
  ...

category.controller.ts

  ...
  @Patch(':id')
  update(
    @Param('id') id: string,
    @Body() updateCategoryDto: UpdateCategoryDto,
  ) {
    return this.categoryService.update({ id: +id, ...updateCategoryDto });
  }
  ...

Schema.prisma

datasource db {
  provider = "sqlite"
  url      = env("DATABASE_URL")
}

generator client {
  provider = "prisma-client-js"
}

model User {
  id           Int            @id @default(autoincrement())
  email        String         @unique
  username     String         @unique
  password     String
  isAdmin      Boolean
  mainCategory MainCategory[]

  projects Project[]
}

model TechStack {
  id             Int           @id @default(autoincrement())
  name           String        @unique
  description    String?
  MainCategory   MainCategory? @relation(fields: [mainCategoryId], references: [id])
  mainCategoryId Int?
  technologies   Technology[]
}

model MainCategory {
  id          Int         @id @default(autoincrement())
  name        String      @unique
  description String?
  User        User?       @relation(fields: [userId], references: [id])
  userId      Int?
  techStack   TechStack[]
}

model Technology {
  id          Int                   @id @default(autoincrement())
  name        String                @unique
  description String?
  status      String
  stars       Int
  TechStack   TechStack?            @relation(fields: [techStackId], references: [id])
  techStackId Int?
  projects    ProjectTechnologies[]
}

model Project {
  id           Int                   @id @default(autoincrement())
  name         String                @unique
  description  String?
  link         String
  technologies ProjectTechnologies[]
  User         User?                 @relation(fields: [userId], references: [id])
  userId       Int?
}

model ProjectTechnologies {
  project      Project    @relation(fields: [projectId], references: [id])
  projectId    Int // relation scalar field (used in the `@relation` attribute above)
  technologies Technology @relation(fields: [technologyId], references: [id])
  technologyId Int // relation scalar field (used in the `@relation` attribute above)

  @@id([projectId, technologyId])
}

From the error shown, it is certain that a number would is definitely expected. But is there a way of telling typescript that its okay to get just a number only without having to write extra code? or altering the auto generated file in any way?

Upvotes: 0

Views: 260

Answers (1)

Tasin Ishmam
Tasin Ishmam

Reputation: 7268

You could create a new type using the generated definition of MainCategoryUncheckedUpdateInput where the id field is of type number.

type customCategoryUpdateInput = Omit<Prisma.MainCategoryUncheckedUpdateInput, "id"> & {
    id?: number; // redifining id to be of type number only 
};

The omit utility is used to first erase the original type definition of id in MainCategoryUncheckedUpdateInput before redefining it. Now you can use customCategoryUpdateInput in place of Prisma.MainCategoryUncheckedUpdateInput in your service file.

Upvotes: 0

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