From 976b2c310ef15bc0e2bff2ce319a81c01c6cc841 Mon Sep 17 00:00:00 2001
From: Yusuke Wada <yusuke@kamawada.com>
Date: Tue, 20 Sep 2022 22:01:03 +0900
Subject: [PATCH] feat: `c.req.body` and `c.req.json` accept generics (#529)

---
 deno_dist/request.ts    | 25 +++++++++++--------------
 deno_dist/utils/body.ts |  8 ++++++--
 src/request.ts          | 25 +++++++++++--------------
 src/utils/body.ts       |  8 ++++++--
 4 files changed, 34 insertions(+), 32 deletions(-)

diff --git a/deno_dist/request.ts b/deno_dist/request.ts
index c70102bd..1e471b0d 100644
--- a/deno_dist/request.ts
+++ b/deno_dist/request.ts
@@ -1,4 +1,5 @@
 import { parseBody } from './utils/body.ts'
+import type { BodyData } from './utils/body.ts'
 import type { Cookie } from './utils/cookie.ts'
 import { parse } from './utils/cookie.ts'
 import { getQueryStringFromURL } from './utils/url.ts'
@@ -33,14 +34,10 @@ declare global {
       (name: string): string
       (): Cookie
     }
-    bodyData?: Record<string, string | File>
-    parseBody: {
-      (): Promise<Record<string, string | File>>
-    }
+    bodyData?: BodyData
+    parseBody<BodyType extends BodyData>(): Promise<BodyType>
     jsonData?: any
-    json: {
-      (): Promise<any>
-    }
+    json<JSONData = any>(): Promise<JSONData>
     data: Data
     valid: {
       (key: string, value: any): Data
@@ -121,23 +118,23 @@ export function extendRequestPrototype() {
     }
   } as InstanceType<typeof Request>['cookie']
 
-  Request.prototype.parseBody = async function (
+  Request.prototype.parseBody = async function <BodyType extends BodyData>(
     this: Request
-  ): Promise<Record<string, string | File>> {
+  ): Promise<BodyType> {
     // Cache the parsed body
-    let body: Record<string, string | File>
+    let body: BodyType
     if (!this.bodyData) {
-      body = await parseBody(this)
+      body = await parseBody<BodyType>(this)
       this.bodyData = body
     } else {
-      body = this.bodyData
+      body = this.bodyData as BodyType
     }
     return body
   } as InstanceType<typeof Request>['parseBody']
 
-  Request.prototype.json = async function (this: Request): Promise<any> {
+  Request.prototype.json = async function <JSONData>(this: Request): Promise<JSONData> {
     // Cache the JSON body
-    let jsonData: any
+    let jsonData: JSONData
     if (!this.jsonData) {
       jsonData = JSON.parse(await this.text())
       this.jsonData = jsonData
diff --git a/deno_dist/utils/body.ts b/deno_dist/utils/body.ts
index 2823cf78..39c278a9 100644
--- a/deno_dist/utils/body.ts
+++ b/deno_dist/utils/body.ts
@@ -1,4 +1,8 @@
-export async function parseBody(r: Request | Response): Promise<Record<string, string | File>> {
+export type BodyData = Record<string, string | number | boolean | File>
+
+export async function parseBody<BodyType extends BodyData>(
+  r: Request | Response
+): Promise<BodyType> {
   let body: Record<string, string | File> = {}
   const contentType = r.headers.get('Content-Type')
   if (
@@ -12,5 +16,5 @@ export async function parseBody(r: Request | Response): Promise<Record<string, s
       return acc
     }, form)
   }
-  return body
+  return body as BodyType
 }
diff --git a/src/request.ts b/src/request.ts
index 810e22c3..efc7c411 100644
--- a/src/request.ts
+++ b/src/request.ts
@@ -1,4 +1,5 @@
 import { parseBody } from './utils/body'
+import type { BodyData } from './utils/body'
 import type { Cookie } from './utils/cookie'
 import { parse } from './utils/cookie'
 import { getQueryStringFromURL } from './utils/url'
@@ -33,14 +34,10 @@ declare global {
       (name: string): string
       (): Cookie
     }
-    bodyData?: Record<string, string | File>
-    parseBody: {
-      (): Promise<Record<string, string | File>>
-    }
+    bodyData?: BodyData
+    parseBody<BodyType extends BodyData>(): Promise<BodyType>
     jsonData?: any
-    json: {
-      (): Promise<any>
-    }
+    json<JSONData = any>(): Promise<JSONData>
     data: Data
     valid: {
       (key: string, value: any): Data
@@ -121,23 +118,23 @@ export function extendRequestPrototype() {
     }
   } as InstanceType<typeof Request>['cookie']
 
-  Request.prototype.parseBody = async function (
+  Request.prototype.parseBody = async function <BodyType extends BodyData>(
     this: Request
-  ): Promise<Record<string, string | File>> {
+  ): Promise<BodyType> {
     // Cache the parsed body
-    let body: Record<string, string | File>
+    let body: BodyType
     if (!this.bodyData) {
-      body = await parseBody(this)
+      body = await parseBody<BodyType>(this)
       this.bodyData = body
     } else {
-      body = this.bodyData
+      body = this.bodyData as BodyType
     }
     return body
   } as InstanceType<typeof Request>['parseBody']
 
-  Request.prototype.json = async function (this: Request): Promise<any> {
+  Request.prototype.json = async function <JSONData>(this: Request): Promise<JSONData> {
     // Cache the JSON body
-    let jsonData: any
+    let jsonData: JSONData
     if (!this.jsonData) {
       jsonData = JSON.parse(await this.text())
       this.jsonData = jsonData
diff --git a/src/utils/body.ts b/src/utils/body.ts
index 2823cf78..39c278a9 100644
--- a/src/utils/body.ts
+++ b/src/utils/body.ts
@@ -1,4 +1,8 @@
-export async function parseBody(r: Request | Response): Promise<Record<string, string | File>> {
+export type BodyData = Record<string, string | number | boolean | File>
+
+export async function parseBody<BodyType extends BodyData>(
+  r: Request | Response
+): Promise<BodyType> {
   let body: Record<string, string | File> = {}
   const contentType = r.headers.get('Content-Type')
   if (
@@ -12,5 +16,5 @@ export async function parseBody(r: Request | Response): Promise<Record<string, s
       return acc
     }, form)
   }
-  return body
+  return body as BodyType
 }