GraphQL codegen schema to Zod schema

The reason for this project is to maintain a single source of truth, between graphql and zod. This is useful for validation on forms. Inspired by codegen-graphql-yup

Configs

• onlyWithValidation: boolean ( default false) If you want to generate an schema for all your input objects definitions with or without the directive put it in true.
• zodSchemasMap: a map of your scalars to a zod type. This is useful for scalars such as EmailAddress that are z.string().email()

Simple use

If you only want to validate the required fields, what you can do is use the plugin in the following way

generates:
  schemas.ts:
    plugins:
      - graphql-codegen-zod

Full Use

If you need more validations than only required fields, you have to follow this steps.

this is because in graphql instrospection we dont have access to directives

• Add the directive in your schema.
• In codegen.yml config use that file like schema.

Directive Schema

directive @validation(
  pattern: String
  min: Int
  max: Int
  requiredMessage: String
  typeOf: String
) on INPUT_FIELD_DEFINITION | ARGUMENT_DEFINITION

Example

result.graphql

directive @validation(
  pattern: String
  min: Int
  max: Int
  requiredMessage: String
  typeOf: String
) on INPUT_FIELD_DEFINITION | ARGUMENT_DEFINITION

input TestInput {
  something: String!
}

input RegisterAddressInput {
  postalCode: TestInput! @validation(requiredMessage: "It field have custom message.")
  state: [String]!
  city: String!
  someNumber: Int @validation(min: 10, max: 20)
  someNumberFloat: Float @validation(min: 10.50, max: 20.50)
  someBoolean: Boolean
  line2: String @validation(min: 10, max: 20)
}

codegen.yml

overwrite: true
schema: "./result.graphql"
generates:
  schemas.ts:
    plugins:
      - graphql-codegen-zod:
          onlyWithValidation: false