feat(fetch): add zstandard decompression support (#4238)

* feat(fetch): add zstandard decompression support

* test(fetch): add a test case for zstandard decompression support

Author: J3m5

lib/web/fetch/index.js

@@ -2155,6 +2155,12 @@ async function httpNetworkFetch (
                   flush: zlib.constants.BROTLI_OPERATION_FLUSH,
                   finishFlush: zlib.constants.BROTLI_OPERATION_FLUSH
                 }))
+              } else if (coding === 'zstd' && typeof zlib.createZstdDecompress === 'function') {
+                // Node.js v23.8.0+ and v22.15.0+ supports Zstandard
+                decoders.push(zlib.createZstdDecompress({
+                  flush: zlib.constants.ZSTD_e_continue,
+                  finishFlush: zlib.constants.ZSTD_e_end
+                }))
               } else {
                 decoders.length = 0
                 break

test/fetch/encoding.js

@@ -5,16 +5,16 @@ const assert = require('node:assert')
 const { createServer } = require('node:http')
 const { once } = require('node:events')
 const { fetch } = require('../..')
-const { createBrotliCompress, createGzip, createDeflate } = require('node:zlib')
+const zlib = require('node:zlib')
 const { closeServerAsPromise } = require('../utils/node-http')
 
 test('content-encoding header is case-iNsENsITIve', async (t) => {
   const contentCodings = 'GZiP, bR'
   const text = 'Hello, World!'
 
   const server = createServer({ joinDuplicateHeaders: true }, (req, res) => {
-    const gzip = createGzip()
-    const brotli = createBrotliCompress()
+    const gzip = zlib.createGzip()
+    const brotli = zlib.createBrotliCompress()
 
     res.setHeader('Content-Encoding', contentCodings)
     res.setHeader('Content-Type', 'text/plain')
@@ -39,8 +39,8 @@ test('response decompression according to content-encoding should be handled in
   const text = 'Hello, World!'
 
   const server = createServer({ joinDuplicateHeaders: true }, (req, res) => {
-    const gzip = createGzip()
-    const deflate = createDeflate()
+    const gzip = zlib.createGzip()
+    const deflate = zlib.createDeflate()
 
     res.setHeader('Content-Encoding', contentCodings)
     res.setHeader('Content-Type', 'text/plain')
@@ -58,3 +58,30 @@ test('response decompression according to content-encoding should be handled in
 
   assert.strictEqual(await response.text(), text)
 })
+
+test('should decompress zstandard response',
+  { skip: typeof zlib.createZstdDecompress !== 'function' },
+  async (t) => {
+    const contentCodings = 'zstd'
+    const text = 'Hello, World!'
+    const server = createServer({ joinDuplicateHeaders: true }, (req, res) => {
+      const zstd = zlib.createZstdCompress()
+
+      res.setHeader('Content-Encoding', contentCodings)
+      res.setHeader('Content-Type', 'text/plain')
+
+      zstd.pipe(res)
+      zstd.write(text)
+      zstd.end()
+    }
+    ).listen(0)
+    t.after(closeServerAsPromise(server))
+
+    await once(server, 'listening')
+    const url = `http://localhost:${server.address().port}`
+
+    const response = await fetch(url)
+    assert.strictEqual(await response.text(), text)
+    assert.strictEqual(response.headers.get('content-encoding'), contentCodings)
+    assert.strictEqual(response.headers.get('content-type'), 'text/plain')
+  })