From 61b86687792c327fd9800eb7e3c1aa136194b8c0 Mon Sep 17 00:00:00 2001
From: islandryu <shimaryuhei@gmail.com>
Date: Sun, 19 Jul 2026 22:12:45 +0900
Subject: [PATCH 1/3] zlib: accept ArrayBuffer dictionary in Zstd

Fixes: https://github.com/nodejs/node/issues/64598
Signed-off-by: islandryu <shimaryuhei@gmail.com>
---
 doc/api/zlib.md                            |  8 ++++++--
 lib/zlib.js                                | 11 ++++++++++-
 test/parallel/test-zlib-zstd-dictionary.js | 16 ++++++++++++++++
 3 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/doc/api/zlib.md b/doc/api/zlib.md
index f32715ba6cc6b2..a06e57c9180c87 100644
--- a/doc/api/zlib.md
+++ b/doc/api/zlib.md
@@ -1099,6 +1099,10 @@ added:
   - v23.8.0
   - v22.15.0
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/64599
+    description: The `dictionary` option can be a `TypedArray`, `DataView`, or
+                 `ArrayBuffer`.
   - version: v26.5.0
     pr-url: https://github.com/nodejs/node/pull/64023
     description: The `rejectGarbageAfterEnd` option was added.
@@ -1115,8 +1119,8 @@ Each Zstd-based class takes an `options` object. All options are optional.
 * `maxOutputLength` {integer} Limits output size when using
   [convenience methods][]. **Default:** [`buffer.kMaxLength`][]
 * `info` {boolean} If `true`, returns an object with `buffer` and `engine`. **Default:** `false`
-* `dictionary` {Buffer} Optional dictionary used to
-  improve compression efficiency when compressing or decompressing data that
+* `dictionary` {Buffer|TypedArray|DataView|ArrayBuffer} Optional dictionary used
+  to improve compression efficiency when compressing or decompressing data that
   shares common patterns with the dictionary.
 * `rejectGarbageAfterEnd` {boolean} If `true`, decompression fails when
   input remains after the first complete compressed stream. **Default:** `false`
diff --git a/lib/zlib.js b/lib/zlib.js
index 47726337cf720d..c7ff90edbb572d 100644
--- a/lib/zlib.js
+++ b/lib/zlib.js
@@ -926,6 +926,15 @@ class Zstd extends ZlibBase {
       });
     }
 
+    let dictionary = opts?.dictionary;
+    if (dictionary !== undefined && !isArrayBufferView(dictionary)) {
+      if (isAnyArrayBuffer(dictionary)) {
+        dictionary = Buffer.from(dictionary);
+      } else {
+        dictionary = undefined;
+      }
+    }
+
     const handle = mode === ZSTD_COMPRESS ?
       new binding.ZstdCompress() : new binding.ZstdDecompress();
 
@@ -938,7 +947,7 @@ class Zstd extends ZlibBase {
       pledgedSrcSize,
       writeState,
       processCallback,
-      opts?.dictionary && isArrayBufferView(opts.dictionary) ? opts.dictionary : undefined,
+      dictionary,
     );
 
     super(opts, mode, handle, zstdDefaultOpts);
diff --git a/test/parallel/test-zlib-zstd-dictionary.js b/test/parallel/test-zlib-zstd-dictionary.js
index 28dde28cb055b7..41b2ab90238c69 100644
--- a/test/parallel/test-zlib-zstd-dictionary.js
+++ b/test/parallel/test-zlib-zstd-dictionary.js
@@ -24,3 +24,19 @@ zlib.zstdCompress(input, { dictionary }, common.mustSucceed((compressed) => {
     assert.strictEqual(decompressed.toString(), input.toString());
   }));
 }));
+
+const baseline = zlib.zstdCompressSync(input, { dictionary }).length;
+
+const arrayBuffer = dictionary.buffer.slice(
+  dictionary.byteOffset, dictionary.byteOffset + dictionary.byteLength);
+const uint8 = new Uint8Array(arrayBuffer);
+const dataView = new DataView(arrayBuffer);
+
+for (const dict of [arrayBuffer, uint8, dataView]) {
+  assert.strictEqual(zlib.zstdCompressSync(input, { dictionary: dict }).length,
+                     baseline);
+
+  const compressed = zlib.zstdCompressSync(input, { dictionary: dict });
+  const decompressed = zlib.zstdDecompressSync(compressed, { dictionary: dict });
+  assert.strictEqual(decompressed.toString(), input.toString());
+}

From 0f815b64e8be7a9f95094cacf068a5bf31eb0da0 Mon Sep 17 00:00:00 2001
From: Ryuhei Shima <65934663+islandryu@users.noreply.github.com>
Date: Mon, 20 Jul 2026 01:12:09 +0900
Subject: [PATCH 2/3] Update lib/zlib.js

Co-authored-by: James M Snell <jasnell@gmail.com>
---
 lib/zlib.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/zlib.js b/lib/zlib.js
index c7ff90edbb572d..11c199bde5d00a 100644
--- a/lib/zlib.js
+++ b/lib/zlib.js
@@ -929,7 +929,7 @@ class Zstd extends ZlibBase {
     let dictionary = opts?.dictionary;
     if (dictionary !== undefined && !isArrayBufferView(dictionary)) {
       if (isAnyArrayBuffer(dictionary)) {
-        dictionary = Buffer.from(dictionary);
+        dictionary = new Uint8Array(dictionary);
       } else {
         dictionary = undefined;
       }

From db7a201f95353aa074084d18859284379714f96d Mon Sep 17 00:00:00 2001
From: islandryu <shimaryuhei@gmail.com>
Date: Mon, 20 Jul 2026 01:20:48 +0900
Subject: [PATCH 3/3] zlib: import Uint8Array from primordials

Signed-off-by: islandryu <shimaryuhei@gmail.com>
---
 lib/zlib.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/zlib.js b/lib/zlib.js
index 11c199bde5d00a..5caaf797c484e7 100644
--- a/lib/zlib.js
+++ b/lib/zlib.js
@@ -33,6 +33,7 @@ const {
   ObjectSetPrototypeOf,
   Symbol,
   Uint32Array,
+  Uint8Array,
 } = primordials;
 
 const {