Optimize ApiFromModules type performance (#42762)

Thanks to David Blass working with us on this! GitOrigin-RevId: df40fd785fd88e79fd1bf2bcc4cca150d42e10f7

Author: thomasballinger

npm-packages/convex/src/server/api.ts

@@ -6,7 +6,7 @@ import {
  RegisteredMutation,
  RegisteredQuery,
 } from "./registration.js";
-import { Expand, UnionToIntersection } from "../type_utils.js";
+import type { UnionToIntersection } from "../type_utils.js";
 import { PaginationOptions, PaginationResult } from "./pagination.js";
 import { functionName } from "./functionName.js";
 import { getFunctionAddress } from "./components/paths.js";
@@ -226,7 +226,7 @@ type FunctionReferencesInModule<Module extends Record<string, any>> = {
  -readonly [ExportName in keyof Module as Module[ExportName]["isConvexFunction"] extends true
  ? ExportName
  : never]: FunctionReferenceFromExport<Module[ExportName]>;
-};
+} & unknown;
 
 /**
  * Given a path to a module and it's type, generate an API type for this module.
@@ -236,11 +236,17 @@ type FunctionReferencesInModule<Module extends Record<string, any>> = {
 type ApiForModule<
  ModulePath extends string,
  Module extends object,
-> = ModulePath extends `${infer First}/${infer Second}`
- ? {
- [_ in First]: ApiForModule<Second, Module>;
- }
- : { [_ in ModulePath]: FunctionReferencesInModule<Module> };
+ LastPathWasSegmented extends boolean,
+> =
+ ModulePath extends SegmentedPath<infer First, infer Rest>
+ ? {
+ [_ in First]: ApiForModule<Rest, Module, true>;
+ }
+ : LastPathWasSegmented extends true
+ ? {
+ [_ in ModulePath]: FunctionReferencesInModule<Module>;
+ }
+ : FunctionReferencesInModule<Module>;
 
 /**
  * Given the types of all modules in the `convex/` directory, construct the type
@@ -253,40 +259,61 @@ type ApiForModule<
  * @public
  */
 export type ApiFromModules<AllModules extends Record<string, object>> =
- FilterApi<
- ApiFromModulesAllowEmptyNodes<AllModules>,
- FunctionReference<any, any, any, any>
- >;
+ keyof AllModules & SegmentedPath extends never
+ ? ApiFromNonSegmentedModules<AllModules>
+ : ApiFromSegmentedModules<AllModules>;
+
+// fast path for cases with no segmented modules
+type ApiFromNonSegmentedModules<AllModules extends Record<string, object>> = {
+ [ModulePath in keyof AllModules as keyof FunctionReferencesInModule<
+ AllModules[ModulePath]
+ > extends never
+ ? never
+ : ModulePath]: FunctionReferencesInModule<AllModules[ModulePath]>;
+};
 
-type ApiFromModulesAllowEmptyNodes<AllModules extends Record<string, object>> =
+type ApiFromSegmentedModules<AllModules extends Record<string, object>> =
  ExpandModulesAndDirs<
- UnionToIntersection<
- {
- [ModulePath in keyof AllModules]: ApiForModule<
-  ModulePath & string,
-  AllModules[ModulePath]
- >;
- }[keyof AllModules]
- >
+ IntersectUnionProperties<{
+ [ModulePath in keyof AllModules as FirstSegment<ModulePath>]: ModulePath extends SegmentedPath<
+ string,
+ infer Rest
+ >
+ ? ApiForModule<Rest, AllModules[ModulePath], true>
+  : ApiForModule<ModulePath & string, AllModules[ModulePath], false>;
+ }>
  >;
 
+type IntersectUnionProperties<O extends object> = {
+ [K in keyof O]: UnionToIntersection<O[K]>;
+};
+
+type SegmentedPath<
+ First extends string = string,
+ Rest extends string = string,
+> = `${First}/${Rest}`;
+
+type FirstSegment<ModulePath> =
+ ModulePath extends SegmentedPath<infer First> ? First : ModulePath;
+
 /**
  * @public
  *
  * Filter a Convex deployment api object for functions which meet criteria,
  * for example all public queries.
  */
-export type FilterApi<API, Predicate> = Expand<{
+export type FilterApi<API, Predicate> = {
  [mod in keyof API as API[mod] extends Predicate
  ? mod
- : API[mod] extends FunctionReference<any, any, any, any>
+ : API[mod] extends AnyFunctionReference
  ? never
- : FilterApi<API[mod], Predicate> extends Record<string, never>
+ : {} extends FilterApi<API[mod], Predicate>
  ? never
  : mod]: API[mod] extends Predicate
  ? API[mod]
  : FilterApi<API[mod], Predicate>;
-}>;
+ // equivalent to Expand without requiring another mapped type
+} & unknown;
 
 /**
  * Given an api of type API and a FunctionReference subtype, return an api object
@@ -365,12 +392,18 @@ export function justSchedulable<API>(
  * The differences are:
  * 1. This version is recursive.
  * 2. This stops recursing when it hits a {@link FunctionReference}.
+ * 3. This omits empty object properties
  */
-type ExpandModulesAndDirs<ObjectType> = ObjectType extends AnyFunctionReference
- ? ObjectType
- : {
- [Key in keyof ObjectType]: ExpandModulesAndDirs<ObjectType[Key]>;
- };
+type ExpandModulesAndDirs<ObjectType> =
+ ObjectType extends Record<string, AnyFunctionReference>
+ ? ObjectType
+ : {
+ [Key in keyof ObjectType as keyof ExpandModulesAndDirs<
+ ObjectType[Key]
+ > extends never
+ ? never
+ : Key]: ExpandModulesAndDirs<ObjectType[Key]>;
+ };
 
 /**
  * A {@link FunctionReference} of any type and any visibility with any