fix: treaty infer status code (#201)

src/treaty2/types.ts

@@ -38,6 +38,14 @@ type ReplaceGeneratorWithAsyncGenerator<
             : RecordType[K]
 } & {}
 
+type Enumerate<N extends number, Acc extends number[] = []> =
+        Acc['length'] extends N ? Acc[number] : Enumerate<N, [...Acc, Acc['length']]>;
+
+type IntegerRange<F extends number, T extends number> = Exclude<Enumerate<T>, Enumerate<F>>;
+
+type SuccessCodeRange = IntegerRange<200, 300>;
+type IsSuccessCode<S extends number> = S extends SuccessCodeRange ? true : false;
+
 type MaybeArray<T> = T | T[]
 type MaybePromise<T> = T | Promise<T>
 
@@ -159,19 +167,19 @@ export namespace Treaty {
 
     export type TreatyResponse<Res extends Record<number, unknown>> =
         | {
-              data: Res[200] extends {
+              data: Res[Extract<keyof Res, SuccessCodeRange>] extends {
                   [ELYSIA_FORM_DATA]: infer Data
               }
                   ? Data
-                  : Res[200]
+                  : Res[Extract<keyof Res, SuccessCodeRange>]
               error: null
               response: Response
               status: number
               headers: RequestInit['headers']
           }
         | {
               data: null
-              error: Exclude<keyof Res, 200> extends never
+              error: Exclude<keyof Res, SuccessCodeRange> extends never
                   ? {
                         status: unknown
                         value: unknown
@@ -185,7 +193,7 @@ export namespace Treaty {
                                 ? Data
                                 : Res[Status]
                         }
-                    }[Exclude<keyof Res, 200>]
+                    }[Exclude<keyof Res, SuccessCodeRange>]
               response: Response
               status: number
               headers: RequestInit['headers']

test/types/treaty2.ts

@@ -1,4 +1,4 @@
-import { Elysia, file, form, t } from 'elysia'
+import { Elysia, file, form, status, t } from 'elysia'
 import { treaty } from '../../src'
 import { expectTypeOf } from 'expect-type'
 
@@ -1064,3 +1064,68 @@ type ValidationError = {
 
     edenClient({ id: '1' }).get()
 }
+
+{
+    const app = new Elysia().get("/", () => status(199, "yay"))
+
+    type App = typeof app
+
+    const edenClient = treaty<App>('http://localhost:3000')
+
+    const { data, error } = await edenClient.get()
+
+    expectTypeOf(data).toEqualTypeOf<unknown>()
+    expectTypeOf(error).toEqualTypeOf<{ status: 199; value: "yay"; } | null>()
+}
+
+{
+    const app = new Elysia().get("/", () => status(200, "yay"))
+
+    type App = typeof app
+
+    const edenClient = treaty<App>('http://localhost:3000')
+
+    const { data, error } = await edenClient.get()
+
+    expectTypeOf(data).toEqualTypeOf<"yay" | null>()
+    expectTypeOf(error).toEqualTypeOf<{ status: unknown; value: unknown; } | null>()
+}
+
+{
+    const app = new Elysia().get("/", () => status(201, "yay"))
+
+    type App = typeof app
+
+    const edenClient = treaty<App>('http://localhost:3000')
+
+    const { data, error } = await edenClient.get()
+
+    expectTypeOf(data).toEqualTypeOf<"yay" | null>()
+    expectTypeOf(error).toEqualTypeOf<{ status: unknown; value: unknown; } | null>()
+}
+
+{
+    const app = new Elysia().get("/", () => status(299, "yay"))
+
+    type App = typeof app
+
+    const edenClient = treaty<App>('http://localhost:3000')
+
+    const { data, error } = await edenClient.get()
+
+    expectTypeOf(data).toEqualTypeOf<"yay" | null>()
+    expectTypeOf(error).toEqualTypeOf<{ status: unknown; value: unknown; } | null>()
+}
+
+{
+    const app = new Elysia().get("/", () => status(300, "yay"))
+
+    type App = typeof app
+
+    const edenClient = treaty<App>('http://localhost:3000')
+
+    const { data, error } = await edenClient.get()
+
+    expectTypeOf(data).toEqualTypeOf<unknown>()
+    expectTypeOf(error).toEqualTypeOf<{ status: 300; value: "yay"; } | null>()
+}