René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Zstd silently ignores an ArrayBuffer passed as the dictionary option","articleBody":"### Version\n\n26.5.0\n\n### Platform\n\n```text\nDarwin 25.5.0 arm64\n```\n\n### Subsystem\n\n_No response_\n\n### What steps will reproduce the bug?\n\n```js\n  const zlib = require('node:zlib');\n  const dict = Buffer.from('the quick brown fox '.repeat(4));\n  const ab = dict.buffer.slice(dict.byteOffset, dict.byteOffset + dict.byteLength);\n\n  console.log(zlib.zstdCompressSync(dict, { dictionary: dict }).length);       // 16 (dict used)\n  console.log(zlib.zstdCompressSync(dict, { dictionary: ab }).length);         // 63 (dict ignored)\n  console.log(zlib.zstdCompressSync(dict).length);                            // 63 (no dict)\n \n```\n\n\n### How often does it reproduce? Is there a required condition?\n\nAlways\n\n### What is the expected behavior? Why is that the expected behavior?\n\nAn ArrayBuffer dictionary is honored.\nBoth frames should be 16.\n\n\n### What do you see instead?\n\nThe ArrayBuffer is silently dropped and zstd compresses with no dictionary (63). \n\n### Additional information\n\nAccording to the [docs](https://nodejs.org/api/zlib.html#class-zstdoptions) this may not be a bug(the Zstd dictionary option is documented as {Buffer} only). \nBut deflate/inflate and Brotli accept an ArrayBuffer, so it would be nice to align Zstd with them.","author":{"url":"https://github.com/islandryu","@type":"Person","name":"islandryu"},"datePublished":"2026-07-19T14:06:34Z","url":"https://github.com/nodejs/node/issues/64598"}