From 952d8efec51622a32b2e91c73aad35c1c579fc0c Mon Sep 17 00:00:00 2001
From: tsctx <91457664+tsctx@users.noreply.github.com>
Date: Wed, 3 Jul 2024 20:15:42 +0900
Subject: [PATCH] feat: implement `BodyReadable.bytes`

---
 lib/api/readable.js           | 42 +++++++++++++++++++++++++++--------
 test/client-request.js        | 26 ++++++++++++++++++++++
 test/types/readable.test-d.ts |  3 +++
 types/dispatcher.d.ts         |  1 +
 types/readable.d.ts           |  5 +++++
 5 files changed, 68 insertions(+), 9 deletions(-)

diff --git a/lib/api/readable.js b/lib/api/readable.js
index a04ca8edca2..a2af6ae9bcd 100644
--- a/lib/api/readable.js
+++ b/lib/api/readable.js
@@ -124,6 +124,11 @@ class BodyReadable extends Readable {
     return consume(this, 'blob')
   }
 
+  // https://fetch.spec.whatwg.org/#dom-body-bytes
+  async bytes () {
+    return consume(this, 'bytes')
+  }
+
   // https://fetch.spec.whatwg.org/#dom-body-arraybuffer
   async arrayBuffer () {
     return consume(this, 'arrayBuffer')
@@ -308,6 +313,31 @@ function chunksDecode (chunks, length) {
   return buffer.utf8Slice(start, bufferLength)
 }
 
+/**
+ * @param {Buffer[]} chunks
+ * @param {number} length
+ * @returns {Uint8Array}
+ */
+function chunksConcat (chunks, length) {
+  if (chunks.length === 0 || length === 0) {
+    return new Uint8Array(0)
+  }
+  if (chunks.length === 1) {
+    // fast-path
+    return new Uint8Array(chunks[1])
+  }
+  const buffer = new Uint8Array(length)
+
+  let offset = 0
+  for (let i = 0; i < chunks.length; ++i) {
+    const chunk = chunks[i]
+    buffer.set(chunk, offset)
+    offset += chunk.length
+  }
+
+  return buffer
+}
+
 function consumeEnd (consume) {
   const { type, body, resolve, stream, length } = consume
 
@@ -317,17 +347,11 @@ function consumeEnd (consume) {
     } else if (type === 'json') {
       resolve(JSON.parse(chunksDecode(body, length)))
     } else if (type === 'arrayBuffer') {
-      const dst = new Uint8Array(length)
-
-      let pos = 0
-      for (const buf of body) {
-        dst.set(buf, pos)
-        pos += buf.byteLength
-      }
-
-      resolve(dst.buffer)
+      resolve(chunksConcat(body, length).buffer)
     } else if (type === 'blob') {
       resolve(new Blob(body, { type: stream[kContentType] }))
+    } else if (type === 'bytes') {
+      resolve(chunksConcat(body, length))
     }
 
     consumeFinish(consume)
diff --git a/test/client-request.js b/test/client-request.js
index 8cbad5ccb48..b015a6408a2 100644
--- a/test/client-request.js
+++ b/test/client-request.js
@@ -655,6 +655,32 @@ test('request arrayBuffer', async (t) => {
   await t.completed
 })
 
+test('request bytes', async (t) => {
+  t = tspl(t, { plan: 2 })
+
+  const obj = { asd: true }
+  const server = createServer((req, res) => {
+    res.end(JSON.stringify(obj))
+  })
+  after(() => server.close())
+
+  server.listen(0, async () => {
+    const client = new Client(`http://localhost:${server.address().port}`)
+    after(() => client.destroy())
+
+    const { body } = await client.request({
+      path: '/',
+      method: 'GET'
+    })
+    const bytes = await body.bytes()
+
+    t.deepStrictEqual(Buffer.from(JSON.stringify(obj)), bytes)
+    t.ok(bytes instanceof Uint8Array)
+  })
+
+  await t.completed
+})
+
 test('request body', async (t) => {
   t = tspl(t, { plan: 1 })
 
diff --git a/test/types/readable.test-d.ts b/test/types/readable.test-d.ts
index d004b706569..b5d32f6c221 100644
--- a/test/types/readable.test-d.ts
+++ b/test/types/readable.test-d.ts
@@ -20,6 +20,9 @@ expectAssignable<BodyReadable>(new BodyReadable())
   // blob
   expectAssignable<Promise<Blob>>(readable.blob())
 
+  // bytes
+  expectAssignable<Promise<Uint8Array>>(readable.bytes())
+
   // arrayBuffer
   expectAssignable<Promise<ArrayBuffer>>(readable.arrayBuffer())
 
diff --git a/types/dispatcher.d.ts b/types/dispatcher.d.ts
index 05f0093c3fd..89350159eab 100644
--- a/types/dispatcher.d.ts
+++ b/types/dispatcher.d.ts
@@ -244,6 +244,7 @@ declare namespace Dispatcher {
     readonly bodyUsed: boolean;
     arrayBuffer(): Promise<ArrayBuffer>;
     blob(): Promise<Blob>;
+    bytes(): Promise<Uint8Array>;
     formData(): Promise<never>;
     json(): Promise<unknown>;
     text(): Promise<string>;
diff --git a/types/readable.d.ts b/types/readable.d.ts
index a5fce8a20d3..c4f052af05e 100644
--- a/types/readable.d.ts
+++ b/types/readable.d.ts
@@ -25,6 +25,11 @@ declare class BodyReadable extends Readable {
    */
   blob(): Promise<Blob>
 
+  /** Consumes and returns the body as an Uint8Array
+   *  https://fetch.spec.whatwg.org/#dom-body-bytes
+   */
+  bytes(): Promise<Uint8Array>
+
   /** Consumes and returns the body as an ArrayBuffer
    *  https://fetch.spec.whatwg.org/#dom-body-arraybuffer
    */