graphql-request/src/layers/3_SelectionSet/types.ts

Minimal GraphQL client supporting Node and browsers for scripts or simple apps.

/* eslint-disable @typescript-eslint/ban-types */

import type { MaybeList, StringNonEmpty, Values } from '../../lib/prelude.js'
import type { TSError } from '../../lib/TSError.js'
import type {
  InputFieldsAllNullable,
  OmitNullableFields,
  PickNullableFields,
  Schema,
  SomeField,
  SomeFields,
} from '../1_Schema/__.js'

export type Query<$Index extends Schema.Index> = Root<$Index, 'Query'>

export type Mutation<$Index extends Schema.Index> = Root<$Index, 'Mutation'>

export type Subscription<$Index extends Schema.Index> = Root<$Index, 'Subscription'>

// dprint-ignore
export type Root<$Index extends Schema.Index, Type extends keyof Schema.Index['Root']> =
  $Index['Root'][Type] extends Schema.Object$2 ?  Object<$Index['Root'][Type], $Index> :
                                                  never

// dprint-ignore
export type Object<$Object extends Schema.Object$2, $Index extends Schema.Index> =
  Fields<$Object['fields'], $Index>

// dprint-ignore
type Fields<$Fields extends SomeFields, $Index extends Schema.Index> =
  &
  {
    [Key in keyof $Fields]?:
      // eslint-disable-next-line
      // @ts-ignore excessive deep error, fixme?
      Field<$Fields[Key], $Index>
  }
  &
  /**
   * Alias support.
   * Allow every field to also be given as a key with this pattern `<field>_as_<alias>: ...`
   */
  {
    [
      Key in keyof $Fields as `${keyof $Fields & string}_as_${StringNonEmpty}`
    ]?:
     Field<$Fields[Key], $Index>
  }
  &
  /**
   * Inline fragments for field groups.
   * @see https://spec.graphql.org/draft/#sec-Inline-Fragments
   */
  {
    ___?: MaybeList<Fields<$Fields, $Index> & FieldDirectives>
  }
  &
  /**
   * Special property to select all scalars.
   */
  {
    $scalars?: ClientIndicator
  }

export type IsSelectScalarsWildcard<SS> = SS extends { $scalars: ClientIndicatorPositive } ? true : false

type FieldOptions = {
  /**
   * When using root type field methods there is no point in directives since there can be
   * no no peer fields with those function that by design target sending one root type field.
   */
  hideDirectives?: boolean
}

type FieldOptionsDefault = { hideDirectives: false }

// dprint-ignore
export type Field<$Field extends SomeField, $Index extends Schema.Index, $Options extends FieldOptions = FieldOptionsDefault> =
  Field_<$Field['type'], $Field, $Index, $Options>

// dprint-ignore
export type Field_<
  $type extends Schema.Output.Any,
  $Field extends SomeField,
  $Index extends Schema.Index,
  $Options extends FieldOptions
> =
  $type extends Schema.Output.Nullable<infer $typeInner>  ? Field_<$typeInner, $Field, $Index, $Options> :
  $type extends Schema.Output.List<infer $typeInner>      ? Field_<$typeInner, $Field, $Index, $Options> :
  $type extends Schema.__typename                         ? NoArgsIndicator :
  $type extends Schema.Scalar.Any                         ? Indicator<$Field> :
  $type extends Schema.Enum                               ? Indicator<$Field> :
  $type extends Schema.Object$2                           ? Object<$type, $Index> & ($Options['hideDirectives'] extends true ? {} : FieldDirectives) & Arguments<$Field> :
  $type extends Schema.Union                              ? Union<$type, $Index> & Arguments<$Field> :
  $type extends Schema.Interface                          ? Interface<$type, $Index> & Arguments<$Field> :
                                                            TSError<'Field', '$Field case not handled', { $Field: $Field }>
// dprint-ignore
type Arguments<$Field extends SomeField> =
  $Field['args'] extends Schema.Args<any>         ? InputFieldsAllNullable<$Field['args']['fields']> extends true  ?  { $?: Args<$Field['args']> } :
                                                                                                                      { $: Args<$Field['args']> } :
                                                  {}

// dprint-ignore
export type Interface<$Node extends Schema.Interface, $Index extends Schema.Index> = 
  & InterfaceDistributed<$Node['implementors'][number], $Index>
  & Fields<
      & $Node['fields']
      & {
          __typename: $Node['implementors'][number]['fields']['__typename']
        },
      $Index
    >

// dprint-ignore
type InterfaceDistributed<$Node extends Schema.Object$2, $Index extends Schema.Index> = 
  $Node extends any
    ? {
      [$typename in $Node['fields']['__typename']['type']['type'] as `on${Capitalize<$typename>}`]?:
        Object<$Node, $Index> & FieldDirectives
    }
    : never

// dprint-ignore
export type Union<$Node extends Schema.Union, $Index extends Schema.Index> =
  & UnionDistributed<$Node['members'][number], $Index>
  & { __typename?: NoArgsIndicator }

// dprint-ignore
type UnionDistributed<$Object extends Schema.Object$2,$Index extends Schema.Index> = 
  $Object extends any
  ? {
     [$typename in $Object['fields']['__typename']['type']['type'] as `on${Capitalize<$typename>}`]?:
        Object<$Object, $Index> & FieldDirectives
    }
  : never

/**
 * Helpers
 * ---------------------------------------------------------------------------------------------------
 */

/**
 * Unions
 */

export type UnionFragmentExtractName<T> = T extends `on${infer $Name}` ? $Name : never
export type UnionExtractFragmentNames<T> = Values<
  {
    [Key in keyof T]: UnionFragmentExtractName<Key>
  }
>
export type OmitOnTypeFragments<T> = {
  [$K in keyof T as $K extends `on${StringNonEmpty}` ? never : $K]: T[$K]
}

/**
 * Aliases
 */

export interface Alias<O extends string = string, T extends string = string> {
  origin: O
  target: T
}

// dprint-ignore
export type ParseAliasExpression<E> =
  E extends `${infer O}_as_${infer T}`  ? Schema.Named.NameParse<O> extends never  ? E :
                                          Schema.Named.NameParse<T> extends never  ? E :
                                          Alias<O, T>
                                        : E

export type AliasNameOrigin<N> = ParseAliasExpression<N> extends Alias<infer O, any> ? O : N

/**
 * Resolve the target of an alias or if is not an alias just pass through the name.
 */
export type AliasNameTarget<N> = ParseAliasExpression<N> extends Alias<any, infer T> ? T : N

export type ResolveAliasTargets<SelectionSet> = {
  [Field in keyof SelectionSet as AliasNameTarget<Field>]: SelectionSet[Field]
}

/**
 * Directives
 */

export namespace Directive {
  export type Include = { $include: boolean | { if?: boolean } }
  export namespace Include {
    export type Positive = { $include: true | { if: true } }
    export type Negative = { $include: false | { if: false } }
  }
  export type Skip = { $skip: boolean | { if?: boolean } }
  export namespace Skip {
    export type Positive = { $skip: true | { if: true } }
    export type Negative = { $skip: false | { if: false } }
  }
  export type Defer = { $defer: boolean | { if?: boolean; label?: string } }
  export namespace Defer {
    export type Positive = { $defer: true | { if: true } }
    export type Negative = { $defer: false | { if: false } }
  }
  export type Stream = { $stream: boolean | { if?: boolean; label?: string; initialCount?: number } }
  export namespace Stream {
    export type Positive = { $stream: true | { if: true } }
    export type Negative = { $stream: false | { if: false } }
  }
}

/**
 * Indicators
 */

/**
 * Should this field be selected?
 */
export type ClientIndicator = ClientIndicatorPositive | ClientIndicatorNegative
export type ClientIndicatorPositive = true | 1
export type ClientIndicatorNegative = false | 0 | undefined

export type OmitNegativeIndicators<$SelectionSet> = {
  [K in keyof $SelectionSet as $SelectionSet[K] extends ClientIndicatorNegative ? never : K]: $SelectionSet[K]
}

/**
 * Field selection in general, with directives support too.
 * If a field directive is given as an indicator then it implies "select this" e.g. `true`/`1`.
 * Of course the semantics of the directive may change the derived type (e.g. `skip` means the field might not show up in the result set)
 */
export type NoArgsIndicator = ClientIndicator | FieldDirectives

// dprint-ignore
export type Indicator<$Field extends SomeField> =
  $Field['args'] extends Schema.Args<any>        ?  InputFieldsAllNullable<$Field['args']['fields']> extends true
                                                      ? ({ $?: Args<$Field['args']> } & FieldDirectives) | ClientIndicator :
                                                        { $: Args<$Field['args']> } & FieldDirectives :
                                                    NoArgsIndicator

// dprint-ignore
export type Args<$Args extends Schema.Args<any>> = ArgFields<$Args['fields']>

// dprint-ignore
export type ArgFields<$ArgFields extends Schema.InputObject['fields']> =
  & {
      [Key in keyof OmitNullableFields<$ArgFields>]: InputField<$ArgFields[Key]>
    }
  & {
      [Key in keyof PickNullableFields<$ArgFields>]?: InputField<$ArgFields[Key]> | null
    }

// dprint-ignore
type InputField<$InputType extends Schema.Input.Any> =
  $InputType extends Schema.Input.Nullable<infer $InnerType>    ? InputField<$InnerType> | null :
  $InputType extends Schema.Input.List<infer $InnerType>        ? InputField<$InnerType>[] :
  $InputType extends Schema.InputObject<infer _, infer $Fields> ? ArgFields<$Fields> :
  $InputType extends Schema.Enum<infer _, infer $Members>       ? $Members[number] :
  $InputType extends Schema.Scalar.Any                          ? ReturnType<$InputType['codec']['decode']> :
                                                                  TSError<'InferTypeInput', 'Unknown $InputType', { $InputType: $InputType }> // never

/**
 * @see https://spec.graphql.org/draft/#sec-Type-System.Directives.Built-in-Directives
 */
export interface FieldDirectives {
  /**
   * https://spec.graphql.org/draft/#sec--skip
   */
  $skip?: boolean | { if?: boolean }
  /**
   * https://spec.graphql.org/draft/#sec--include
   */
  $include?: boolean | { if?: boolean }
  /**
   * @see https://github.com/graphql/graphql-wg/blob/main/rfcs/DeferStream.md#defer
   */
  $defer?: boolean | { if?: boolean; label?: string }
  /**
   * @see https://github.com/graphql/graphql-wg/blob/main/rfcs/DeferStream.md#stream
   */
  $stream?: boolean | { if?: boolean; label?: string; initialCount?: number }
}