Codegen
PluginsFlowresolvers

Flow Resolvers

Package nameWeekly DownloadsVersionLicenseUpdated
@graphql-codegen/flow-resolversDownloadsVersionLicenseSep 5th, 2024

Installation

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

This plugin generates resolvers signature based on your GraphQLSchema.

It generates types for your entire schema: types, input types, enum, interface, scalar and union.

This plugin requires you to use @graphql-codegen/flow as well, because it depends on it’s types.

Config API Reference

addUnderscoreToArgsType

type: boolean

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

Usage Examples

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         addUnderscoreToArgsType: true
       },
     },
   },
 };
 export default config;

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.

Usage Examples

Custom Context Type
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         contextType: 'MyContext'
       },
     },
   },
 };
 export default config;
Custom Context Type
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         contextType: './my-types#MyContext'
       },
     },
   },
 };
 export default config;

fieldContextTypes

type: Array_1

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

Usage Examples

Custom Field Context Types
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         fieldContextTypes: ['MyType.foo#CustomContextType', 'MyType.bar#./my-file#ContextTypeOne']
       },
     },
   },
 };
 export default config;

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.

Usage Examples

Custom RootValue Type
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         rootValueType: 'MyRootValue'
       },
     },
   },
 };
 export default config;
Custom RootValue Type
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         rootValueType: './my-types#MyRootValue'
       },
     },
   },
 };
 export default config;

directiveContextTypes

type: Array_1

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.

Usage Examples

Directive Context Extender
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         directiveContextTypes: ['myCustomDirectiveName#./my-file#CustomContextExtender']
       },
     },
   },
 };
 export default config;

mapperTypeSuffix

type: string

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

Usage Examples

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         mapperTypeSuffix: 'Model'
       },
     },
   },
 };
 export default config;

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.

Usage Examples

Custom Context Type
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         mappers: {
           User: './my-models#UserDbObject',
           Book: './my-models#Collections',
         }
       },
     },
   },
 };
 export default config;

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.

Usage Examples

Replace with any
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         defaultMapper: 'any',
       },
     },
   },
 };
 export default config;
Custom Base Object
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         defaultMapper: './my-file#BaseObject',
       },
     },
   },
 };
 export default config;
Wrap default types with Partial

You can also specify a custom wrapper for the original type, without overriding the original generated types, use {T} to specify the identifier. (for flow, use $Shape<{T}>)

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         defaultMapper: 'Partial<{T}>',
       },
     },
   },
 };
 export default config;
Allow deep partial with utility-types
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       plugins: ['typescript', 'typescript-resolver', { add: { content: "import { DeepPartial } from 'utility-types';" } }],
       config: {
         defaultMapper: 'DeepPartial<{T}>',
       },
     },
   },
 };
 export default config;

avoidOptionals

type: AvoidOptionalsConfig_2 | boolean default: false

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

Usage Examples

Override all definition types
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       plugins: ['typescript', 'typescript-resolver'],
       config: {
         avoidOptionals: true
       },
     },
   },
 };
 export default config;
Override only specific definition types
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       plugins: ['typescript', 'typescript-resolver'],
       config: {
         avoidOptionals: {
           field: true,
           inputValue: true,
           object: true,
           defaultValue: true,
         }
       },
     },
   },
 };
 export default config;

showUnusedMappers

type: boolean default: true

Warns about unused mappers.

Usage Examples

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       plugins: ['typescript', 'typescript-resolver'],
       config: {
         showUnusedMappers: true,
       },
     },
   },
 };
 export default config;

enumValues

type: EnumValuesMap_2

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 default: Promise<T> | T

Allow you to override resolverTypeWrapper definition.

federation

type: boolean default: false

Supports Apollo Federation

enumPrefix

type: boolean default: true

Allow you to disable prefixing for generated enums, works in combination with typesPrefix.

Usage Examples

Disable enum prefixes
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       plugins: ['typescript', 'typescript-resolver'],
       config: {
         typesPrefix: 'I',
         enumPrefix: false
       },
     },
   },
 };
 export default config;

optionalResolveType

type: boolean default: false

Sets the __resolveType field as optional field.

immutableTypes

type: boolean default: false

Generates immutable types by adding readonly to properties and uses ReadonlyArray.

namespacedImportName

type: string default: ''

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.

resolverTypeSuffix

type: string default: Resolvers

Suffix we add to each generated type resolver.

allResolversTypeName

type: string default: Resolvers

The type name to use when exporting all resolvers signature as unified type.

internalResolversPrefix

type: string default: '__'

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.

onlyResolveTypeForInterfaces

type: boolean default: false

Turning this flag to true will generate resolver signature that has only resolveType for interfaces, forcing developers to write inherited type resolvers in the type itself.

strictScalars

type: boolean default: false

Makes scalars strict.

If scalars are found in the schema that are not defined in scalars an error will be thrown during codegen.

Usage Examples

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         strictScalars: true,
       },
     },
   },
 };
 export default config;

defaultScalarType

type: string default: any

Allows you to override the type that unknown scalars will have.

Usage Examples

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         defaultScalarType: 'unknown'
       },
     },
   },
 };
 export default config;

scalars

type: ScalarsMap

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

Usage Examples

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         scalars: {
           DateTime: 'Date',
           JSON: '{ [key: string]: any }',
         }
       },
     },
   },
 };
 export default config;

namingConvention

type: NamingConvention default: change-case-all#pascalCase

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

Usage Examples

Override All Names
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         namingConvention: 'change-case-all#lowerCase',
       },
     },
   },
 };
 export default config;
Upper-case enum values
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         namingConvention: {
           typeNames: 'change-case-all#pascalCase',
           enumValues: 'change-case-all#upperCase',
         }
       },
     },
   },
 };
 export default config;
Keep names as is
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
        namingConvention: 'keep',
       },
     },
   },
 };
 export default config;
Remove Underscores
codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         namingConvention: {
           typeNames: 'change-case-all#pascalCase',
           transformUnderscore: true
         }
       },
     },
   },
 };
 export default config;

typesPrefix

type: string default: (empty)

Prefixes all the generated types.

Usage Examples

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         typesPrefix: 'I',
       },
     },
   },
 };
 export default config;

typesSuffix

type: string default: (empty)

Suffixes all the generated types.

Usage Examples

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         typesSuffix: 'I',
       },
     },
   },
 };
 export default config;

skipTypename

type: boolean default: false

Does not add __typename to the generated types, unless it was specified in the selection set.

Usage Examples

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         skipTypename: true
       },
     },
   },
 };
 export default config;

nonOptionalTypename

type: boolean default: false

Automatically adds __typename field to the generated types, even when they are not specified in the selection set, and makes it non-optional

Usage Examples

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         nonOptionalTypename: true
       },
     },
   },
 };
 export default config;

useTypeImports

type: boolean default: false

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

Usage Examples

codegen.ts
 import type { CodegenConfig } from '@graphql-codegen/cli';
 
 const config: CodegenConfig = {
   // ...
   generates: {
     'path/to/file': {
       // plugins...
       config: {
         useTypeImports: true
       },
     },
   },
 };
 export default config;

dedupeFragments

type: boolean default: false

Removes fragment duplicates for reducing data transfer. It is done by removing sub-fragments imports from fragment definition Instead - all of them are imported to the Operation node.

inlineFragmentTypes

type: string default: inline

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).

emitLegacyCommonJSImports

type: boolean default: true

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

💡

Quick Start with flow-resolvers

You can find a blog post we wrote about using and customizing this plugin here, it refers to typescript-resolvers but everything there is relevant to flow-resolvers as well.

Enum Resolvers

Apollo-Server and schemas built with graphql-tools supports creating resolvers for GraphQL enums.

This is helpful because you can have internal values that are different from the public enum values, and you can use the internal values in your resolvers.

Codegen allows you to specify either mappers or enumValues to map enums in your resolvers, and if you are using it for enums, you’ll get a resolver signature for the enum resolvers as well.

Usage Example

With the following schema:

type Query {
  favoriteColor: Color!
}
 
enum Color {
  RED
  BLUE
}
schema: schema.graphql
generates:
  ./resolvers-types.js:
    config:
      enumValues:
        Color: ./enums#ColorsCode
    plugins:
      - flow
      - flow-resolvers
enums.ts
export enum ColorsCode {
  MY_RED = '#FF0000',
  MY_BLUE = '#0000FF'
}
resolvers.ts
import type { Resolvers } from './resolvers-types'
import { ColorsCode } from './enums'
 
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
  }
}

You can also define the same with explicit enum values:

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

Or, with mappers:

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