Codegen
PluginsJavakotlin

Kotlin

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

Installation

npm i -D @graphql-codegen/kotlin

Config API Reference

package

type: string

Customize the Java package name. The default package name will be generated according to the output file path.

Usage Examples

generates:
  src/main/kotlin/my-org/my-app/Resolvers.kt:
    plugins:
      - kotlin
    config:
      package: custom.package.name

enumValues

type: EnumValuesMap_2

Overrides the default value of enum values declared in your GraphQL schema.

Usage Examples

  config:
    enumValues:
      MyEnum:
        A: 'foo'

listType

type: string default: Iterable

Allow you to customize the list type

Usage Examples

generates:
  src/main/kotlin/my-org/my-app/Types.kt:
    plugins:
      - kotlin
    config:
      listType: Map

withTypes

type: boolean default: false

Allow you to enable generation for the types

Usage Examples

generates:
  src/main/kotlin/my-org/my-app/Types.kt:
    plugins:
      - kotlin
    config:
      withTypes: true

omitJvmStatic

type: boolean default: false

Allow you to omit JvmStatic annotation

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.

The kotlin plugin generates Kotlin classes for Enums and Input types.

You can use this plugin to generate Java enums based on your GraphQL schema, and it also generates a type-safe Kotlin transformer for GraphQL input types.

Prepare your environment

To get started with these plugins and preset, make sure you have the following installed:

  • Node.js (10 or later)
  • NPM or Yarn

Run the following in your Android project:

npm init --yes
npm install graphql
npm install -D @graphql-codegen/cli @graphql-codegen/kotlin

Then, create codegen.yml with the following configuration:

schema: POINT_TO_YOUR_SCHEMA
documents: POINT_TO_YOUR_GRAPHQL_OPERATIONS
generates:
  ./app/src/Types.kt:
    plugins:
      - kotlin
💡
Also, make sure to add node_modules to your .gitignore file.
java-resolversoperations