Type improvements for selection maps

Author: incetarik

CHANGELOG.md

@@ -3,6 +3,10 @@ This file contains the changes made to the package.
 
 The sections are in descending order of the change date.
 
+## [0.1.7] - 2022-04-27
+### Changed
+- Type improvements for `selectionMap` option.
+
 ## [0.1.6] - 2022-04-27
 ### Added
 - Changelog file.
@@ -17,5 +21,6 @@ object.
 The initial version of the package.
 
 [Unreleased]: https://github.com/incetarik/nestjs-prisma-dynamic-resolvers/compare/v1.0.0...HEAD
+[0.1.7]: https://github.com/incetarik/nestjs-prisma-dynamic-resolvers/compare/0.1.6...0.1.7
 [0.1.6]: https://github.com/incetarik/nestjs-prisma-dynamic-resolvers/compare/0.1.5...0.1.6
 [0.1.5]: https://github.com/incetarik/nestjs-prisma-dynamic-resolvers/releases/tag/0.1.5

src/dynamic-resolvers.ts

@@ -27,7 +27,7 @@ export interface IOnResolvingParams<P extends object = object> {
   readonly resolveInfo: GraphQLResolveInfo
 }
 
-export interface IOnResolvedParams<R extends object, P extends object = object> extends IOnResolvingParams<P> {
+export interface IOnResolvedParams<R = any, P extends object = object> extends IOnResolvingParams<P> {
   /**
    * The data resolved by the resolver.
    *
@@ -43,7 +43,7 @@ export interface IOnResolvedParams<R extends object, P extends object = object>
  * @export
  * @interface IUseDynamicResolversParams
  */
-export interface IUseDynamicResolversParams<R extends object = object, P extends object = object> {
+export interface IUseDynamicResolversParams {
   /**
    * The name of the module that will contain the resolver.
    *
@@ -93,7 +93,7 @@ export interface IUseDynamicResolversParams<R extends object = object, P extends
    * An event function that will be triggered when the resolver is about to resolve the defined navigation.
    *
    * @param {IOnResolvingParams<P>} params The parameters.
-   * @return {(Promise<R | undefined | void> | R | undefined | void)} The
+   * @return {*} The
    * replace value.
    * 
    * If this function returns a value from this event function, then the
@@ -102,13 +102,13 @@ export interface IUseDynamicResolversParams<R extends object = object, P extends
    * 
    * @memberof IUseDynamicResolversParams
    */
-  onResolving?(params: IOnResolvingParams<P>): Promise<R | undefined | void> | R | undefined | void
+  onResolving?<P extends object>(params: IOnResolvingParams<P>): any
 
   /**
    * An event function that will be triggered when the resolved is resolved the defined navigation.
    *
-   * @param {IOnResolvedParams<R, P>} params The parameters.
-   * @return {(Promise<R | undefined | void> | undefined | void)} The
+   * @param {IOnResolvedParams<any, P>} params The parameters.
+   * @return {*} The
    * replace value.
    * 
    * If this function returns a value from this event function, then the
@@ -117,7 +117,7 @@ export interface IUseDynamicResolversParams<R extends object = object, P extends
    * 
    * @memberof IUseDynamicResolversParams
    */
-  onResolved?(params: IOnResolvedParams<R, P>): Promise<R | undefined | void> | undefined | void
+  onResolved?<P extends object = object>(params: IOnResolvedParams<any, P>): any
 }
 
 export interface IRegisterDynamicResolverParams extends IUseDynamicResolversParams {

src/helpers/extract-grapql-selections.ts

@@ -11,12 +11,14 @@ import { FieldNode, GraphQLResolveInfo, Kind } from 'graphql'
  *
  * @export
  * @interface IGraphQLExtractSelectionMap
+ * @template T The type of the source.
+ * @template K The keys included of the source.
  */
-export interface IGraphQLExtractSelectionMap {
-  [ k: string ]: string | ((parentKeys: string[], fieldName: string) => string)
+export type IGraphQLExtractSelectionMap<T extends object = object, K extends keyof T = Exclude<ObjectKeys<T>, KeysMatching<T, Date>>> = {
+  [ k in K ]?: string | ((parentKeys: string[], fieldName: K) => string)
 }
 
-export interface IExtractGraphQLSelectionsParams {
+interface IExtractGraphQLSelectionsParams<T extends object = object, K extends keyof T = Exclude<ObjectKeys<T>, KeysMatching<T, Date>>> {
   /**
    * The root node of the GraphQL request.
    *
@@ -28,10 +30,10 @@ export interface IExtractGraphQLSelectionsParams {
   /**
    * The map for renaming the field names to database navigation keys.
    *
-   * @type {IGraphQLExtractSelectionMap}
+   * @type {IGraphQLExtractSelectionMap<T, K>}
    * @memberof IParams
    */
-  selectionMap?: IGraphQLExtractSelectionMap
+  selectionMap?: IGraphQLExtractSelectionMap<T, K>
 
   /**
    * The name array of the parent fields.
@@ -51,8 +53,10 @@ export interface IExtractGraphQLSelectionsParams {
  * extraction.
  * 
  * @return {*} An object of `selected` field names.
+ * @template T The type of the source.
+ * @template K The keys included of the source.
  */
-export function extractGraphQLSelections(params: IExtractGraphQLSelectionsParams) {
+export function extractGraphQLSelections<T extends object = object, K extends keyof T = Exclude<ObjectKeys<T>, KeysMatching<T, Date>>>(params: IExtractGraphQLSelectionsParams<T, K>) {
   const { node, parentFieldKeys = [], selectionMap = {} } = params
 
   const { selectionSet } = node
@@ -69,7 +73,7 @@ export function extractGraphQLSelections(params: IExtractGraphQLSelectionsParams
         parentFieldKeys: [ ...parentFieldKeys, fieldName ]
       })
 
-      const mapper = selectionMap[ fieldName ]
+      const mapper = selectionMap[ fieldName as keyof typeof selectionMap ] as any
       let mappedValue: string
       if (typeof mapper === 'string') {
         mappedValue = mapper
@@ -97,7 +101,7 @@ export function extractGraphQLSelections(params: IExtractGraphQLSelectionsParams
   }, {} as Record<string, any>)
 }
 
-export interface IExtractGraphQLSelectionPathParams {
+interface IExtractGraphQLSelectionPathParams<T extends object = object, K extends keyof T = Exclude<ObjectKeys<T>, KeysMatching<T, Date>>> {
   /**
    * The initial path of the request.
    *
@@ -109,11 +113,11 @@ export interface IExtractGraphQLSelectionPathParams {
   /**
    * The map for renaming the field names to database navigation keys.
    *
-   * @type {IGraphQLExtractSelectionMap}
+   * @type {IGraphQLExtractSelectionMap<T, K>}
    * @memberof IParams
    * @default {}
    */
-  selectionMap?: IGraphQLExtractSelectionMap
+  selectionMap?: IGraphQLExtractSelectionMap<T, K>
 
   /**
    * The initial root paths.
@@ -131,10 +135,14 @@ export interface IExtractGraphQLSelectionPathParams {
  * @export
  * @param {IExtractGraphQLSelectionPathParams} params The parameters for
  * extraction.
+ * 
  * @return {string[]} An array containing field names from the outer level to
  * the inner level.
+ * 
+ * @template T The type of the source.
+ * @template K The keys included of the source.
  */
-export function extractGraphQLSelectionPath(params: IExtractGraphQLSelectionPathParams): string[] {
+export function extractGraphQLSelectionPath<T extends object = object, K extends keyof T = Exclude<ObjectKeys<T>, KeysMatching<T, Date>>>(params: IExtractGraphQLSelectionPathParams<T, K>): string[] {
   const { path, selectionMap = {}, rootPaths = [] } = params
   if (typeof path !== 'object') return rootPaths
 
@@ -145,7 +153,7 @@ export function extractGraphQLSelectionPath(params: IExtractGraphQLSelectionPath
     rootPaths
   })
 
-  const mapper = selectionMap[ key ]
+  const mapper = selectionMap[ key as keyof typeof selectionMap ] as any
   let mappedValue: string
   if (typeof mapper === 'string') {
     mappedValue = mapper

src/index.ts

@@ -3,9 +3,7 @@ export {
   extractGraphQLSelectionPath,
   extractGraphQLSelections,
   provideDynamicResolvers,
-  IExtractGraphQLSelectionPathParams,
   IGraphQLExtractSelectionMap,
-  IExtractGraphQLSelectionsParams as IParams,
 } from './helpers'
 
 export { NavigationProperty } from './navigation-property'

types.d.ts

@@ -7,3 +7,59 @@ declare type KeysMatching<T, V> = { [ K in keyof T ]-?: T[ K ] extends V ? K : n
  * A Dictionary type for keeping `TValue` values.
  */
 declare type Dictionary<TValue> = { [ key: string ]: TValue }
+
+/**
+ * Maps the given type to its function keys.
+ * If the given type is an array, then the function indices will be returned.
+ * If the given type is an object, then the function keys will be returned.
+ */
+declare type FunctionKeys<T>
+  = T extends any[]
+  ? Exclude<_FunctionKeys<T>, -1>
+  : T extends { [ key: string ]: any }
+  ? KeysMatching<T, Func>
+  : never
+
+/**
+ * Defines the nullable version of given type.
+ */
+declare type Nullable<T> = T | null | undefined
+
+/**
+ * Defines the nullable version of given type with `void` type.
+ */
+declare type NullableReturn<T> = Nullable<T> | void
+
+/**
+ * Defines a type which can be in a promise or not.
+ */
+declare type MaybePromise<T> = Promise<T> | T
+
+/**
+ * Gets the keys of an object whose values are objects.
+ *
+ * This does not include function keys.
+ */
+declare type ObjectKeys<T extends object>
+  = Exclude<KeysMatching<T, object>, FunctionKeys<T>>
+
+/**
+ * Gets the length of an array.
+ */
+declare type Length<T extends any[]> = T extends { length: infer L } ? L : never
+
+/**
+* Builds a tuple with given length.
+*/
+declare type BuildTuple<L extends number, T extends any[] = []>
+  = T extends { length: L } ? T : BuildTuple<L, [ ...T, any ]>
+
+type _FunctionKeys<TArray extends any[], CurrentIndex = 0, Index = -1>
+  = TArray extends [ infer H, ...infer T ]
+  ? H extends Func
+  ? _FunctionKeys<T, Add<CurrentIndex, 1>, Index | CurrentIndex>
+  : _FunctionKeys<T, Add<CurrentIndex, 1>, Index>
+  : Index
+
+type Add<A extends number, B extends number> =
+  Length<[ ...BuildTuple<A>, ...BuildTuple<B> ]>