fix: use JsonValue from type-fest as body type fixes: #245

Author: TheDadi

package.json

@@ -35,6 +35,7 @@
     "@types/koa": "^3.0.0",
     "co-body": "^6.2.0",
     "formidable": "^3.5.4",
+    "type-fest": "^5.3.1",
     "zod": "^4.1.12"
   },
   "devDependencies": {

pnpm-lock.yaml

@@ -1,5 +1,6 @@
 import * as coBody from 'co-body';
 import type { Middleware, Next } from 'koa';
+import type { JsonValue } from 'type-fest';
 import type { KoaBodyMiddlewareOptions, ScalarOrArrayFiles } from './types.js';
 import { KoaBodyMiddlewareOptionsSchema } from './types.js';
 import {
@@ -17,15 +18,15 @@ export * from './types.js';
 
 declare module 'koa' {
   interface Request {
-    body?: { [key: string]: unknown } | string;
+    body?: JsonValue;
     rawBody?: string;
     files?: ScalarOrArrayFiles;
   }
 }
 
 declare module 'http' {
   interface IncomingMessage {
-    body?: { [key: string]: unknown } | string;
+    body?: JsonValue;
     rawBody?: string;
     files?: ScalarOrArrayFiles;
   }

src/index.ts

@@ -1,15 +1,10 @@
 import type { Context } from 'koa';
+import type { JsonValue } from 'type-fest';
 import type { ParseWithFormidableResult } from './parse-with-formidable.js';
 
-export type ParseWithCoBodyTextResult = string;
-export type ParseWithCoBodyJsonResult = { [key: string]: unknown };
-export type ParseWithCoBodyUrlEncodedResult = { [key: string]: unknown };
 export type ParseWithCoBodyIncludeUnparsedResult = { parsed: ParseWithCoBodyResult; raw: string };
 
-export type ParseWithCoBodyResult =
-  | ParseWithCoBodyTextResult
-  | ParseWithCoBodyJsonResult
-  | ParseWithCoBodyUrlEncodedResult;
+export type ParseWithCoBodyResult = JsonValue;
 
 type PatchOptions = {
   isMultipart: string | boolean | null;
@@ -35,7 +30,7 @@ export function patchNodeAndKoa(
       ctx.req.body = parsed;
       ctx.req.rawBody = raw;
     } else {
-      ctx.req.body = body;
+      ctx.req.body = body as ParseWithCoBodyResult;
     }
   }
   if (patchKoa) {
@@ -48,7 +43,7 @@ export function patchNodeAndKoa(
       ctx.request.body = parsed;
       ctx.request.rawBody = raw;
     } else {
-      ctx.request.body = body;
+      ctx.request.body = body as ParseWithCoBodyResult;
     }
   }
 }