fix(rest): Keep custom endpoints in resource().extend({...}); type process() params in every options form

.agents/skills/data-client-rest-setup/references/RestEndpoint.md

@@ -778,8 +778,8 @@ Override this for advanced cases like extracting headers alongside the body.
 
 Perform any transforms with the parsed result. Defaults to identity function (do nothing).
 
-`args` are the arguments the endpoint was called with. In [extend()](#extend), they are typed from the
-resulting endpoint's [path](#path), [searchParams](#searchParams) and [body](#body).
+`args` are the arguments the endpoint was called with. They are typed from the endpoint's [path](#path),
+[searchParams](#searchParams) and [body](#body), including those set in the same [extend()](#extend) call.
 
 ```ts
 const getUser = new RestEndpoint({ path: '/users/:id' });

.agents/skills/data-client-rest-setup/references/RestEndpoint.vue.md

@@ -778,8 +778,8 @@ Override this for advanced cases like extracting headers alongside the body.
 
 Perform any transforms with the parsed result. Defaults to identity function (do nothing).
 
-`args` are the arguments the endpoint was called with. In [extend()](#extend), they are typed from the
-resulting endpoint's [path](#path), [searchParams](#searchParams) and [body](#body).
+`args` are the arguments the endpoint was called with. They are typed from the endpoint's [path](#path),
+[searchParams](#searchParams) and [body](#body), including those set in the same [extend()](#extend) call.
 
 ```ts
 const getUser = new RestEndpoint({ path: '/users/:id' });

.agents/skills/data-client-rest/references/RestEndpoint.md

@@ -778,8 +778,8 @@ Override this for advanced cases like extracting headers alongside the body.
 
 Perform any transforms with the parsed result. Defaults to identity function (do nothing).
 
-`args` are the arguments the endpoint was called with. In [extend()](#extend), they are typed from the
-resulting endpoint's [path](#path), [searchParams](#searchParams) and [body](#body).
+`args` are the arguments the endpoint was called with. They are typed from the endpoint's [path](#path),
+[searchParams](#searchParams) and [body](#body), including those set in the same [extend()](#extend) call.
 
 ```ts
 const getUser = new RestEndpoint({ path: '/users/:id' });

.agents/skills/data-client-rest/references/RestEndpoint.vue.md

@@ -778,8 +778,8 @@ Override this for advanced cases like extracting headers alongside the body.
 
 Perform any transforms with the parsed result. Defaults to identity function (do nothing).
 
-`args` are the arguments the endpoint was called with. In [extend()](#extend), they are typed from the
-resulting endpoint's [path](#path), [searchParams](#searchParams) and [body](#body).
+`args` are the arguments the endpoint was called with. They are typed from the endpoint's [path](#path),
+[searchParams](#searchParams) and [body](#body), including those set in the same [extend()](#extend) call.
 
 ```ts
 const getUser = new RestEndpoint({ path: '/users/:id' });

.changeset/extend-process-params.md

@@ -2,9 +2,9 @@
 '@data-client/rest': patch
 ---
 
-Type the `params` and `body` that `process()` receives in `.extend()`
+Type the `params` and `body` that `process()` receives in `RestEndpoint` options
 
-A `process(value, params)` method passed to `RestEndpoint.extend()` or `resource().extend('get', {...})` used to get `params` typed as `any`, so a typo or a wrong assumption about a path parameter went unnoticed until runtime. They are now typed from the extended endpoint's `path`, `searchParams` and `body`, including a `path` set in the same `.extend()` call.
+A `process(value, params)` method passed to `new RestEndpoint()`, `RestEndpoint.extend()` or `resource().extend()` used to get `params` typed as `any`, so a typo or a wrong assumption about a path parameter went unnoticed until runtime. They are now typed from the endpoint's `path`, `searchParams` and `body`, including a `path` set in the same `.extend()` call.
 
 ```ts
 const getUser = new RestEndpoint({ path: '/users/:id' });

.changeset/resource-extend-keeps-members.md

@@ -0,0 +1,17 @@
+---
+'@data-client/rest': patch
+---
+
+Fix `resource().extend({ get: ... })` dropping endpoints added earlier from its type
+
+Customizing a resource's standard endpoints with `.extend({ ... })` kept every endpoint at runtime, but TypeScript lost the ones added before it with `.extend('name', options)`, and the deprecated `create`. Using them was a type error even though they worked.
+
+```ts
+const UserResource = resource({ path: '/users/:id', schema: User })
+  .extend('current', { path: '/user' })
+  .extend({ get: { dataExpiryLength: 60000 } });
+
+// Before: Property 'current' does not exist
+// After: no error
+const me = await ctrl.fetch(UserResource.current);
+```

docs/rest/api/RestEndpoint.md

@@ -900,8 +900,8 @@ Override this for advanced cases like extracting headers alongside the body.
 
 Perform any transforms with the parsed result. Defaults to identity function (do nothing).
 
-`args` are the arguments the endpoint was called with. In [extend()](#extend), they are typed from the
-resulting endpoint's [path](#path), [searchParams](#searchParams) and [body](#body).
+`args` are the arguments the endpoint was called with. They are typed from the endpoint's [path](#path),
+[searchParams](#searchParams) and [body](#body), including those set in the same [extend()](#extend) call.
 
 ```ts
 const getUser = new RestEndpoint({ path: '/users/:id' });

packages/rest/src-4.1-types/resourceExtendable.d.ts

@@ -2,7 +2,7 @@ import type { EndpointInterface, EndpointToFunction } from '@data-client/endpoin
 import type { ResourcePath } from './pathTypes.js';
 import type { ResourceExtension, ResourceEndpointExtensions, CustomResource, ExtendedResource } from './resourceExtensionTypes.js';
 import type { ResourceGenerics, ResourceInterface } from './resourceTypes.js';
-import type { ExtendableRestGenerics, PartialRestGenerics, RestEndpointExtendOptions, RestExtendedEndpoint, RestInstanceBase } from './RestEndpoint.js';
+import type { ExtendableRestGenerics, RestEndpointExtendOptions, RestExtendedEndpoint, RestInstanceBase } from './RestEndpoint.js';
 export interface Extendable<O extends ResourceGenerics = {
     path: ResourcePath;
     schema: any;
@@ -15,7 +15,7 @@ export interface Extendable<O extends ResourceGenerics = {
     }, ExtendKey extends string, ExtendOptions extends ExtendableRestGenerics | {}>(this: R, key: ExtendKey, options: Readonly<RestEndpointExtendOptions<ExtendOptions, R['get'], EndpointToFunction<R['get']>> & ExtendOptions> & ExtendOptions): R & {
         [key in ExtendKey]: RestExtendedEndpoint<ExtendOptions, R['get']>;
     };
-    extend<R extends ResourceInterface, Get extends PartialRestGenerics = {}, GetList extends PartialRestGenerics = {}, Update extends PartialRestGenerics = {}, PartialUpdate extends PartialRestGenerics = {}, Delete extends PartialRestGenerics = {}>(this: R, options: ResourceEndpointExtensions<R, Get, GetList, Update, PartialUpdate, Delete>): CustomResource<R, O, Get, GetList, Update, PartialUpdate, Delete>;
+    extend<R extends ResourceInterface, Get extends ExtendableRestGenerics = {}, GetList extends ExtendableRestGenerics = {}, Update extends ExtendableRestGenerics = {}, PartialUpdate extends ExtendableRestGenerics = {}, Delete extends ExtendableRestGenerics = {}>(this: R, options: ResourceEndpointExtensions<R, Get, GetList, Update, PartialUpdate, Delete>): CustomResource<R, O, Get, GetList, Update, PartialUpdate, Delete> & Omit<R, keyof ResourceInterface | 'extend'>;
     extend<R extends ResourceInterface, T extends Record<string, EndpointInterface>>(this: R, extender: (baseResource: R) => T): ExtendedResource<R, T>;
 }
 //# sourceMappingURL=resourceExtendable.d.ts.map

packages/rest/src/RestEndpointTypes.ts

@@ -272,13 +272,7 @@ export type RestEndpointExtendOptions<
   OptionsToFunction<O, E, F>,
   'schema' extends keyof O ? Extract<O['schema'], Schema | undefined>
   : E['schema']
-> & {
-  /** @see https://dataclient.io/rest/api/RestEndpoint#process */
-  process?(
-    value: any,
-    ...args: ProcessArgs<Parameters<OptionsToFunction<O, E, F>>>
-  ): any;
-} &
+> &
   // Same as Partial<Omit<E, ExtendOmitKeys>>, but skips the per-key Exclude<> work
   // (and the double mapped type) when E has no members beyond the standard ones.
   // Keep the guard inside the mapped type's keys: a `? unknown : ...` conditional
@@ -288,44 +282,13 @@ export type RestEndpointExtendOptions<
     keyof E extends ExtendOmitKeys ? never : Exclude<keyof E, ExtendOmitKeys>
   >;
 
-/** Parameters<F> as a single tuple, so process() accepts every way the endpoint can be called.
- * Endpoints with optional params or body have a union like `[params] | []` or `[params, body] | [body]`
- * (see ParamFetchNoBody/ParamFetchWithBody); it merges position-wise, with an element optional when
- * some call omits it. A single tuple (like a custom `fetch(params?)`) is kept as is.
- * Only for contextually typing an options callback: TypeScript can't infer callback parameters from a
- * union of tuples. The instance `process()` keeps `Parameters<F>`, the stricter signature for callers.
+/** Argument I passed to process(), from Parameters<F>.
+ * Indexing a union like `[params] | []` or `[params, body] | [body]` (see ParamFetchNoBody/ParamFetchWithBody)
+ * merges position-wise, giving `undefined` where some call omits the argument.
+ * Endpoints that take no args keep `any`, so process(value, params: any) and similar still compile.
  */
-type ProcessArgs<A extends readonly any[]> =
-  // fast path for fixed-length tuples; [A['length']] can't be checked against a union of lengths
-  number extends A['length'] ? A
-  : [A['length']] extends [0] ? A
-  : [A['length']] extends [1] ? A
-  : [A['length']] extends [2] ? A
-  : IsUnion<A> extends false ? A
-  : [] extends A ?
-    [ArgAt1<A>] extends [never] ?
-      [params?: ArgAt0<A>]
-    : [params?: ArgAt0<A>, body?: ArgAt1<A>]
-  : [params: ArgAt0<A>, body?: ArgAt1<A>];
-type IsUnion<T, U = T> =
-  T extends any ?
-    [U] extends [T] ?
-      false
-    : true
-  : never;
-// Distribute over the union; the length check gives never for a position a call omits
-type ArgAt0<A extends readonly any[]> =
-  A extends unknown ?
-    A['length'] extends 0 ?
-      never
-    : A[0]
-  : never;
-type ArgAt1<A extends readonly any[]> =
-  A extends unknown ?
-    A['length'] extends 0 | 1 ?
-      never
-    : A[1]
-  : never;
+type ProcessArg<A extends readonly any[], I extends 0 | 1> =
+  [A['length']] extends [0] ? any : A[I];
 
 type ExtendOmitKeys =
   KeyofRestEndpoint | keyof PartialRestGenerics | keyof RestEndpointOptions;
@@ -475,8 +438,9 @@ export type RestExtendedEndpoint<
   (keyof E extends KeyofRestEndpoint ? unknown
   : Omit<E, KeyofRestEndpoint | keyof O>);
 
-/** PartialRestGenerics without `process`. extend() constrains its options to this, so the
- * `process` member of RestEndpointExtendOptions is the only contextual type for process() params.
+/** PartialRestGenerics without `process`. Options passed to the constructor, extend() and
+ * resource().extend() are constrained by this, so RestEndpointOptions' typed `process` member is
+ * the only contextual type for process() params.
  */
 export interface ExtendableRestGenerics {
   /** @see https://dataclient.io/rest/api/RestEndpoint#path */
@@ -507,6 +471,10 @@ export interface PartialRestGenerics extends ExtendableRestGenerics {
 export interface RestGenerics extends PartialRestGenerics {
   readonly path: string;
 }
+/** RestGenerics without `process`; see ExtendableRestGenerics */
+interface ConstructorRestGenerics extends ExtendableRestGenerics {
+  readonly path: string;
+}
 
 export type PaginationEndpoint<
   E extends FetchFunction & RestGenerics & { sideEffect?: boolean | undefined },
@@ -695,6 +663,15 @@ export interface RestEndpointOptions<
   fetch?: F;
   key?(...args: Parameters<F>): string;
   url?(...args: Parameters<F>): string;
+  /** @see https://dataclient.io/rest/api/RestEndpoint#process */
+  // Positional rather than a rest tuple: when F is generic (like a path type parameter),
+  // a deferred rest tuple would reject process(value, params) for having too many params.
+  process?(
+    value: any,
+    params: ProcessArg<Parameters<F>, 0>,
+    body: ProcessArg<Parameters<F>, 1>,
+    ...rest: any[]
+  ): any;
   update?: EndpointUpdateFunction<F, S>;
 }
 
@@ -754,7 +731,7 @@ export interface RestEndpointConstructor {
    *
    * @see https://dataclient.io/rest/api/RestEndpoint
    */
-  new <O extends RestGenerics = any>({
+  new <O extends ConstructorRestGenerics = any>({
     method,
     sideEffect,
     name,

packages/rest/src/resourceExtendable.ts

@@ -17,7 +17,6 @@ import type {
 } from './resourceTypes.js';
 import type {
   ExtendableRestGenerics,
-  PartialRestGenerics,
   RestEndpointExtendOptions,
   RestExtendedEndpoint,
   RestInstanceBase,
@@ -72,11 +71,11 @@ export interface Extendable<
   };
   extend<
     R extends ResourceInterface,
-    Get extends PartialRestGenerics = {},
-    GetList extends PartialRestGenerics = {},
-    Update extends PartialRestGenerics = {},
-    PartialUpdate extends PartialRestGenerics = {},
-    Delete extends PartialRestGenerics = {},
+    Get extends ExtendableRestGenerics = {},
+    GetList extends ExtendableRestGenerics = {},
+    Update extends ExtendableRestGenerics = {},
+    PartialUpdate extends ExtendableRestGenerics = {},
+    Delete extends ExtendableRestGenerics = {},
   >(
     this: R,
     options: ResourceEndpointExtensions<
@@ -87,7 +86,9 @@ export interface Extendable<
       PartialUpdate,
       Delete
     >,
-  ): CustomResource<R, O, Get, GetList, Update, PartialUpdate, Delete>;
+  ): CustomResource<R, O, Get, GetList, Update, PartialUpdate, Delete> &
+    // keeps members like those added by extend('key', options)
+    Omit<R, keyof ResourceInterface | 'extend'>;
   extend<
     R extends ResourceInterface,
     T extends Record<string, EndpointInterface>,

packages/rest/src/resourceExtensionTypes.ts

@@ -8,6 +8,7 @@ import type { ResourcePath } from './pathTypes.js';
 import { Extendable } from './resourceExtendable.js';
 import { ResourceGenerics, ResourceInterface } from './resourceTypes.js';
 import type {
+  ExtendableRestGenerics,
   PartialRestGenerics,
   RestExtendedEndpoint,
   RestInstanceBase,
@@ -59,11 +60,11 @@ export type ExtendedResource<
 
 export interface ResourceEndpointExtensions<
   R extends ResourceInterface,
-  Get extends PartialRestGenerics = {},
-  GetList extends PartialRestGenerics = {},
-  Update extends PartialRestGenerics = {},
-  PartialUpdate extends PartialRestGenerics = {},
-  Delete extends PartialRestGenerics = {},
+  Get extends ExtendableRestGenerics = {},
+  GetList extends ExtendableRestGenerics = {},
+  Update extends ExtendableRestGenerics = {},
+  PartialUpdate extends ExtendableRestGenerics = {},
+  Delete extends ExtendableRestGenerics = {},
 > {
   readonly get?: RestEndpointOptions<
     unknown extends Get ? EndpointToFunction<R['get']>

packages/rest/typescript-tests/extendOptions.test.ts

@@ -0,0 +1,45 @@
+// Options passed to extend() are checked against their types, and
+// resource().extend() keeps every member of the resource it extends.
+// Each @ts-expect-error line must keep erroring; plain lines must keep compiling.
+import { User } from '__tests__/new';
+
+import resource from '../src/resource';
+import RestEndpoint from '../src/RestEndpoint';
+
+const ep = new RestEndpoint({ path: '/users/:id', schema: User });
+const UserResource = resource({ path: '/users/:id', schema: User });
+
+/* ---------------- option types (plain ep.extend() is in extendPathsGetPage) ---------------- */
+// @ts-expect-error
+ep.extend({ path: '/u/:uid' }).extend({ dataExpiryLength: 'long' });
+// @ts-expect-error
+ep.extend({ path: '/u/:uid', dataExpiryLength: 'long' });
+// @ts-expect-error
+UserResource.get.extend({ dataExpiryLength: 'long' });
+// @ts-expect-error
+UserResource.extend('get', { dataExpiryLength: 'long' });
+// @ts-expect-error
+UserResource.extend('current', { dataExpiryLength: 'long' });
+// @ts-expect-error
+UserResource.extend({ get: { dataExpiryLength: 'long' } });
+
+/* ---------------- resource().extend() keeps members ---------------- */
+const CurrentUserResource = UserResource.extend('current', {
+  path: '/user',
+}).extend({ get: { dataExpiryLength: 1000 } });
+export const current = CurrentUserResource.current();
+export const get = CurrentUserResource.get({ id: 5 });
+// deprecated, but still there at runtime
+export const create = CurrentUserResource.create;
+// @ts-expect-error not a member
+CurrentUserResource.other;
+
+// extend({...}) results can be extended again
+const Chained = CurrentUserResource.extend({
+  update: { dataExpiryLength: 5 },
+}).extend('me', { path: '/me' });
+export const chained = [
+  Chained.current(),
+  Chained.me(),
+  Chained.get({ id: 1 }),
+];