Flow Resolvers

          npm i -D @graphql-codegen/flow-resolvers
        

          yarn add -D @graphql-codegen/flow-resolvers
        

          pnpm add -D @graphql-codegen/flow-resolvers
        

          bun add -D @graphql-codegen/flow-resolvers
        

Config API Reference

addUnderscoreToArgsType

type: boolean

Adds _ to generated Args types in order to avoid duplicate identifiers.

contextType

type: string

Use this configuration to set a custom type for your context, and it will affect all the resolvers, without the need to override it using generics each time. If you wish to use an external type and import it from another file, you can use add plugin and add the required import statement, or you can use a module#type syntax.

fieldContextTypes

type: object

Use this to set a custom type for a specific field context. It will only affect the targeted resolvers. You can either use Field.Path#ContextTypeName or Field.Path#ExternalFileName#ContextTypeName

rootValueType

type: string

Use this configuration to set a custom type for the rootValue, and it will affect resolvers of all root types (Query, Mutation and Subscription), without the need to override it using generics each time. If you wish to use an external type and import it from another file, you can use add plugin and add the required import statement, or you can use both module#type or module#namespace#type syntax.

directiveContextTypes

type: object

Use this to set a custom type for a specific field context decorated by a directive. It will only affect the targeted resolvers. You can either use Field.Path#ContextTypeName or Field.Path#ExternalFileName#ContextTypeName

ContextTypeName should by a generic Type that take the context or field context type as only type parameter.

mapperTypeSuffix

type: string

Adds a suffix to the imported names to prevent name clashes.

mappers

type: object

Replaces a GraphQL type usage with a custom type, allowing you to return custom object from your resolvers. You can use both module#type and module#namespace#type syntax.

defaultMapper

type: string

Allow you to set the default mapper when it’s not being override by mappers or generics. You can specify a type name, or specify a string in module#type or module#namespace#type format. The default value of mappers is the TypeScript type generated by typescript package.

avoidOptionals

type: object

This will cause the generator to avoid using optionals (?), so all field resolvers must be implemented in order to avoid compilation errors. Default value: “false”

showUnusedMappers

type: boolean

Warns about unused mappers. Default value: “true”

enumValues

type: object

Overrides the default value of enum values declared in your GraphQL schema, supported in this plugin because of the need for integration with typescript package. See documentation under typescript plugin for more information and examples.

resolverTypeWrapperSignature

type: string

Allow you to override resolverTypeWrapper definition. Default value: “Promise | T”

federation

type: boolean

Supports Apollo Federation Default value: “false”

customDirectives

type: object

Configures behavior for custom directives from various GraphQL libraries.

optionalResolveType

type: boolean

Sets the __resolveType field as optional field. Default value: “false”

immutableTypes

type: boolean

Generates immutable types by adding readonly to properties and uses ReadonlyArray. Default value: “false”

namespacedImportName

type: string

Prefixes all GraphQL related generated types with that value, as namespaces import. You can use this feature to allow separation of plugins to different files. Default value: ””“

resolverTypeSuffix

type: string

Suffix we add to each generated type resolver. Default value: “Resolvers”

allResolversTypeName

type: string

The type name to use when exporting all resolvers signature as unified type. Default value: “Resolvers”

internalResolversPrefix

type: string

Defines the prefix value used for __resolveType and __isTypeOf resolvers. If you are using mercurius-js, please set this field to empty string for better compatibility. Default value: ”’__‘“

resolversNonOptionalTypename

type: object

Makes __typename of resolver mappings non-optional without affecting the base types. Default value: “false”

avoidCheckingAbstractTypesRecursively

type: boolean

If true, recursively goes through all object type’s fields, checks if they have abstract types and generates expected types correctly. This may not work for cases where provided default mapper types are also nested e.g. defaultMapper: DeepPartial<{T}> or defaultMapper: Partial<{T}>. Default value: “false”

addInterfaceFieldResolverTypes

type: boolean

If true, add field resolver types to Interfaces. By default, GraphQL Interfaces do not trigger any field resolvers, meaning every implementing type must implement the same resolver for the shared fields.

Some tools provide a way to change the default behaviour by making GraphQL Objects inherit missing resolvers from their Interface types. In these cases, it is fine to turn this option to true.

For example, if you are using @graphql-tools/schema#makeExecutableSchema with inheritResolversFromInterfaces: true, you can make addInterfaceFieldResolverTypes: true as well https://the-guild.dev/graphql/tools/docs/generate-schema#makeexecutableschema Default value: “false”

strictScalars

type: boolean

Makes scalars strict.

If scalars are found in the schema that are not defined in scalars an error will be thrown during codegen. Default value: “false”

defaultScalarType

type: string

Allows you to override the type that unknown scalars will have. Default value: “unknown”

scalars

type: object

Extends or overrides the built-in scalars and custom GraphQL scalars to a custom type.

namingConvention

type: object

Allow you to override the naming convention of the output. You can either override all namings, or specify an object with specific custom naming convention per output. The format of the converter must be a valid module#method. Allowed values for specific output are: typeNames, enumValues. You can also use “keep” to keep all GraphQL names as-is. Additionally, you can set transformUnderscore to true if you want to override the default behavior, which is to preserve underscores.

Available case functions in change-case-all are camelCase, capitalCase, constantCase, dotCase, headerCase, noCase, paramCase, pascalCase, pathCase, sentenceCase, snakeCase, lowerCase, localeLowerCase, lowerCaseFirst, spongeCase, titleCase, upperCase, localeUpperCase and upperCaseFirst See more Default value: “change-case-all#pascalCase”

typesPrefix

type: string

Prefixes all the generated types. Default value: ""

typesSuffix

type: string

Suffixes all the generated types. Default value: ""

enumPrefix

type: boolean

Allow you to disable prefixing for generated enums, works in combination with typesPrefix. Default value: “true”

enumSuffix

type: boolean

Allow you to disable suffixing for generated enums, works in combination with typesSuffix. Default value: “true”

useTypeImports

type: boolean

Will use import type {} rather than import {} when importing only types. This gives compatibility with TypeScript’s “importsNotUsedAsValues”: “error” option Default value: “false”

inlineFragmentTypes

type: string

Whether fragment types should be inlined into other operations. “inline” is the default behavior and will perform deep inlining fragment types within operation type definitions. “combine” is the previous behavior that uses fragment type references without inlining the types (and might cause issues with deeply nested fragment that uses list types). “mask” transforms the types for use with fragment masking. Useful when masked types are needed when not using the “client” preset e.g. such as combining it with Apollo Client’s data masking feature. Default value: “inline”

emitLegacyCommonJSImports

type: boolean

Emit legacy common js imports. Default it will be true this way it ensure that generated code works with non-compliant bundlers. Default value: “true”

importExtension

type: object

Append this extension to all imports. Useful for ESM environments that require file extensions in import statements.

printFieldsOnNewLines

type: boolean

If you prefer to have each field in generated types printed on a new line, set this to true. This can be useful for improving readability of the resulting types, without resorting to running tools like Prettier on the output. Default value: “false”

includeExternalFragments

type: boolean

Whether to include external fragments in the generated code. External fragments are not defined in the same location as the operation definition. Default value: “false”

type Query {
  favoriteColor: Color!
}

enum Color {
  RED
  BLUE
}

schema: schema.graphql
generates:
  ./resolvers-types.js:
    config:
      enumValues:
        Color: ./enums#ColorsCode
    plugins:
      - flow
      - flow-resolvers

export enum ColorsCode {
  MY_RED = '#FF0000',
  MY_BLUE = '#0000FF'
}

import { ColorsCode } from './enums'
import type { Resolvers } from './resolvers-types'

const resolvers: Resolvers = {
  Color: {
    RED: ColorsCode.MY_RED,
    BLUE: ColorsCode.MY_BLUE
  },
  Query: {
    favoriteColor: () => ColorsCode.MY_RED // Now you cn return this, and it will be mapped to your actual GraphQL enum
  }
}

schema: schema.graphql
generates:
  ./resolvers-types.js:
    config:
      enumValues:
        Color:
          RED: '#FF0000'
          BLUE: '#0000FF'
    plugins:
      - flow
      - flow-resolvers

schema: schema.graphql
generates:
  ./resolvers-types.js:
    config:
      mappers:
        Color: ./enums#ColorsCode
    plugins:
      - flow
      - flow-resolvers