feat: enable nested routers by introducing RecursivelyProcessAppRouter (#138)

* feat: enable nested routers by introducing RecursivelyProcessAppRouter

* refactor: move getValue to express lib

* test: move getValue tests to express lib

Author: oliverbutler

.changeset/popular-bikes-greet.md

@@ -0,0 +1,5 @@
+---
+'@ts-rest/core': minor
+---
+
+Enable nested routers without declaring new constants

libs/ts-rest/core/src/lib/dsl.ts

@@ -1,5 +1,3 @@
-import { Narrow } from './type-utils';
-
 /**
  * The path with colon-prefixed parameters
  * e.g. "/posts/:id".
@@ -37,6 +35,19 @@ export type AppRouteMutation = {
   responses: Record<number, unknown>;
 };
 
+/**
+ * Recursively process a router, allowing for you to define nested routers.
+ *
+ * The main purpose of this is to convert all path strings into string constants so we can infer the path
+ */
+type RecursivelyProcessAppRouter<T extends AppRouter> = {
+  [K in keyof T]: T[K] extends AppRoute
+    ? T[K]
+    : T[K] extends AppRouter
+    ? RecursivelyProcessAppRouter<T[K]>
+    : T[K];
+};
+
 /**
  * A union of all possible endpoint types.
  */
@@ -67,17 +78,17 @@ type ContractInstance = {
   /**
    * A collection of routes or routers
    */
-  router: <T extends AppRouter>(endpoints: Narrow<T>) => T;
+  router: <T extends AppRouter>(endpoints: RecursivelyProcessAppRouter<T>) => T;
   /**
    * A single query route, should exist within
    * a {@link AppRouter}
    */
-  query: <T extends AppRouteQuery>(query: Narrow<T>) => T;
+  query: <T extends AppRouteQuery>(query: T) => T;
   /**
    * A single mutation route, should exist within
    * a {@link AppRouter}
    */
-  mutation: <T extends AppRouteMutation>(mutation: Narrow<T>) => T;
+  mutation: <T extends AppRouteMutation>(mutation: T) => T;
   /**
    * Exists to allow storing a Type in the contract (at compile time only)
    */
@@ -103,9 +114,7 @@ export const initContract = (): ContractInstance => {
   return {
     // @ts-expect-error - this is a type error, but it's not clear how to fix it
     router: (args) => args,
-    // @ts-expect-error - this is a type error, but it's not clear how to fix it
     query: (args) => args,
-    // @ts-expect-error - this is a type error, but it's not clear how to fix it
     mutation: (args) => args,
     response: <T>() => undefined as unknown as T,
     body: <T>() => undefined as unknown as T,

libs/ts-rest/core/src/lib/type-utils.spec.ts

@@ -1,6 +1,6 @@
 /* eslint-disable @typescript-eslint/no-unused-vars */
 import { z } from 'zod';
-import { getValue, ZodInferOrType } from './type-utils';
+import { ZodInferOrType } from './type-utils';
 
 const zodObject = z.object({ title: z.string() });
 type Test1 = ZodInferOrType<typeof zodObject>;
@@ -11,37 +11,3 @@ type Test2 = ZodInferOrType<typeof zodObject>;
 type Test3 = ZodInferOrType<{ title: string }>;
 
 it.todo('should infer type');
-
-describe('getValue', () => {
-  it('should get one level deep', () => {
-    const obj = {
-      title: 'Title',
-    };
-
-    const value = getValue(obj, 'title');
-
-    expect(value).toBe('Title');
-  });
-
-  it('should get one level deep with nullable', () => {
-    const obj = {
-      title: 'Title',
-    };
-
-    const value = getValue(obj, 'test', null);
-
-    expect(value).toBe(null);
-  });
-
-  it('should get two levels deep', () => {
-    const obj = {
-      sub: {
-        text: 'text',
-      },
-    };
-
-    const value = getValue(obj, 'sub.text');
-
-    expect(value).toBe('text');
-  });
-});

libs/ts-rest/core/src/lib/type-utils.ts

@@ -37,26 +37,6 @@ export type GetFieldType<T, P> = P extends `${infer Left}.${infer Right}`
     : undefined
   : undefined;
 
-export function getValue<
-  TData,
-  TPath extends string,
-  TDefault = GetFieldType<TData, TPath>
->(
-  data: TData,
-  path: TPath,
-  defaultValue?: TDefault
-): GetFieldType<TData, TPath> | TDefault {
-  const value = path
-    .split(/[.[\]]/)
-    .filter(Boolean)
-    .reduce<GetFieldType<TData, TPath>>(
-      (value, key) => (value as any)?.[key],
-      data as any
-    );
-
-  return value !== undefined ? value : (defaultValue as TDefault);
-}
-
 // https://stackoverflow.com/questions/63447660/typescript-remove-all-properties-with-particular-type
 // Nested solution also available ^
 type ExcludeKeysWithTypeOf<T, V> = {
@@ -74,21 +54,6 @@ export type ZodInferOrType<T> = T extends ZodTypeAny ? z.infer<T> : T;
 
 export type Merge<T, U> = Omit<T, keyof U> & U;
 
-type Try<A, B, C> = A extends B ? A : C;
-
-type NarrowRaw<T> =
-  // eslint-disable-next-line @typescript-eslint/ban-types
-  | (T extends Function ? T : never)
-  | (T extends string | number | bigint | boolean ? T : never)
-  | (T extends [] ? [] : never)
-  | {
-      [K in keyof T]: K extends 'description' ? T[K] : NarrowNotZod<T[K]>;
-    };
-
-type NarrowNotZod<T> = Try<T, ZodType, NarrowRaw<T>>;
-
-export type Narrow<T> = Try<T, [], NarrowNotZod<T>>;
-
 export type PartialBy<T, K extends keyof T> = Omit<T, K> & Partial<Pick<T, K>>;
 
 // https://github.com/ts-essentials/ts-essentials/blob/4c451652ba7c20b0e0b965e0b7755fd4d7844127/lib/types.ts#L228

libs/ts-rest/express/src/lib/ts-rest-express.spec.ts

@@ -0,0 +1,35 @@
+import { getValue } from './ts-rest-express';
+
+describe('getValue', () => {
+  it('should get one level deep', () => {
+    const obj = {
+      title: 'Title',
+    };
+
+    const value = getValue(obj, 'title');
+
+    expect(value).toBe('Title');
+  });
+
+  it('should get one level deep with nullable', () => {
+    const obj = {
+      title: 'Title',
+    };
+
+    const value = getValue(obj, 'test', null);
+
+    expect(value).toBe(null);
+  });
+
+  it('should get two levels deep', () => {
+    const obj = {
+      sub: {
+        text: 'text',
+      },
+    };
+
+    const value = getValue(obj, 'sub.text');
+
+    expect(value).toBe('text');
+  });
+});

libs/ts-rest/express/src/lib/ts-rest-express.ts

@@ -6,14 +6,34 @@ import {
   AppRouteQuery,
   AppRouter,
   checkZodSchema,
-  getValue,
+  GetFieldType,
   isAppRoute,
   parseJsonQueryObject,
   PathParamsWithCustomValidators,
   Without,
   ZodInferOrType,
 } from '@ts-rest/core';
 
+export function getValue<
+  TData,
+  TPath extends string,
+  TDefault = GetFieldType<TData, TPath>
+>(
+  data: TData,
+  path: TPath,
+  defaultValue?: TDefault
+): GetFieldType<TData, TPath> | TDefault {
+  const value = path
+    .split(/[.[\]]/)
+    .filter(Boolean)
+    .reduce<GetFieldType<TData, TPath>>(
+      (value, key) => (value as any)?.[key],
+      data as any
+    );
+
+  return value !== undefined ? value : (defaultValue as TDefault);
+}
+
 export type ApiRouteResponse<T> = {
   [K in keyof T]: {
     status: K;