zlib: add support for brotli compression dictionary

[rokob]

This change adds JS API support for custom compression dictionaries with Brotli in the zlib library. The underlying Brotli dependency already supports this and zstd exposes something similar. This follows the zstd approach for using a custom dictionary but for Brotli.

Fixes: #52250

Notes

I wanted to get the change up here first to get feedback and ensure the API makes sense. I can then update any relevant docs. The tests

[addaleax]

nice!

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/71305/

[codecov]

Codecov Report

❌ Patch coverage is 80.64516% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.74%. Comparing base (3819c7f) to head (f733e95).
⚠️ Report is 25 commits behind head on main.

Files with missing lines	Patch %	Lines
src/node_zlib.cc	72.09%	6 Missing and 6 partials ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #61763   +/-   ##
=======================================
  Coverage   89.74%   89.74%           
=======================================
  Files         675      675           
  Lines      204642   204729   +87     
  Branches    39322    39333   +11     
=======================================
+ Hits       183657   183744   +87     
+ Misses      13257    13253    -4     
- Partials     7728     7732    +4     

Files with missing lines	Coverage Δ
lib/zlib.js	98.30% <100.00%> (+0.02%)	⬆️
src/node_zlib.cc	77.79% <72.09%> (-0.27%)	⬇️

... and 42 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[rokob]

I updated the initializer to use an r-value ref and added some argument validation on the js side along with some tests. Linters all pass locally for me.

[rokob]

I ran make format-cpp locally which passed which I realized looking at the actions was not setting the CLANG_FORMAT_START variable correctly. I set that locally which captured the issues that showed up in CI and fixed those. My bad.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/71325/

[nodejs-github-bot]

Commit Queue failed

- Loading data for nodejs/node/pull/61763
✔  Done loading data for nodejs/node/pull/61763
----------------------------------- PR info ------------------------------------
Title      zlib: add support for brotli compression dictionary (#61763)
   ⚠  Could not retrieve the email or name of the PR author's from user's GitHub profile!
Branch     rokob:aw-52250-brotli-dict -> nodejs:main
Labels     c++, zlib, author ready, needs-ci
Commits    3
 - zlib: add support for brotli compression dictionary
 - Fix lint, convert to r-value ref instead of string_view, add tests
 - Actually fix the lint
Committers 1
 - Andy Weiss <andy.weiss@reddit.com>
PR-URL: https://github.com/nodejs/node/pull/61763
Fixes: https://github.com/nodejs/node/issues/52250
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
------------------------------ Generated metadata ------------------------------
PR-URL: https://github.com/nodejs/node/pull/61763
Fixes: https://github.com/nodejs/node/issues/52250
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
--------------------------------------------------------------------------------
   ℹ  This PR was created on Tue, 10 Feb 2026 15:54:25 GMT
   ✔  Approvals: 4
   ✔  - Anna Henningsen (@addaleax): https://github.com/nodejs/node/pull/61763#pullrequestreview-3791926125
   ✔  - Colin Ihrig (@cjihrig): https://github.com/nodejs/node/pull/61763#pullrequestreview-3784656650
   ✔  - James M Snell (@jasnell) (TSC): https://github.com/nodejs/node/pull/61763#pullrequestreview-3788840436
   ✔  - Gürgün Dayıoğlu (@gurgunday): https://github.com/nodejs/node/pull/61763#pullrequestreview-3793564199
   ⚠  GitHub cannot link the author of 'zlib: add support for brotli compression dictionary' to their GitHub account.
   ⚠  Please suggest them to take a look at https://github.com/nodejs/node/blob/99b1ada/doc/guides/contributing/pull-requests.md#step-1-fork
   ⚠  GitHub cannot link the author of 'Fix lint, convert to r-value ref instead of string_view, add tests' to their GitHub account.
   ⚠  Please suggest them to take a look at https://github.com/nodejs/node/blob/99b1ada/doc/guides/contributing/pull-requests.md#step-1-fork
   ⚠  GitHub cannot link the author of 'Actually fix the lint' to their GitHub account.
   ⚠  Please suggest them to take a look at https://github.com/nodejs/node/blob/99b1ada/doc/guides/contributing/pull-requests.md#step-1-fork
   ✔  Last GitHub CI successful
   ℹ  Last Full PR CI on 2026-02-12T16:11:42Z: https://ci.nodejs.org/job/node-test-pull-request/71325/
- Querying data for job/node-test-pull-request/71325/
✔  Build data downloaded
   ✔  Last Jenkins CI successful
--------------------------------------------------------------------------------
   ✔  No git cherry-pick in progress
   ✔  No git am in progress
   ✔  No git rebase in progress
--------------------------------------------------------------------------------
- Bringing origin/main up to date...
From https://github.com/nodejs/node
 * branch                  main       -> FETCH_HEAD
✔  origin/main is now up-to-date
- Downloading patch for 61763
From https://github.com/nodejs/node
 * branch                  refs/pull/61763/merge -> FETCH_HEAD
✔  Fetched commits as 3d30c302c37f..f733e95c098a
--------------------------------------------------------------------------------
Auto-merging lib/zlib.js
[main 61638f9171] zlib: add support for brotli compression dictionary
 Author: Andy Weiss <andy.weiss@reddit.com>
 Date: Tue Feb 10 10:45:22 2026 -0500
 3 files changed, 168 insertions(+), 11 deletions(-)
 create mode 100644 test/parallel/test-zlib-brotli-dictionary.js
Auto-merging lib/zlib.js
[main ca6e6c1767] Fix lint, convert to r-value ref instead of string_view, add tests
 Author: Andy Weiss <andy.weiss@reddit.com>
 Date: Wed Feb 11 11:46:32 2026 -0500
 3 files changed, 84 insertions(+), 24 deletions(-)
[main 3777af02ab] Actually fix the lint
 Author: Andy Weiss <andy.weiss@reddit.com>
 Date: Thu Feb 12 08:59:07 2026 -0500
 1 file changed, 12 insertions(+), 11 deletions(-)
   ✔  Patches applied
There are 3 commits in the PR. Attempting autorebase.
(node:743) [DEP0190] DeprecationWarning: Passing args to a child process with shell option true can lead to security vulnerabilities, as the arguments are not escaped, only concatenated.
(Use `node --trace-deprecation ...` to show where the warning was created)
Rebasing (2/6)
Executing: git node land --amend --yes
   ⚠  Found Fixes: https://github.com/nodejs/node/issues/52250, skipping..
--------------------------------- New Message ----------------------------------
zlib: add support for brotli compression dictionary
This change adds JS API support for custom compression dictionaries

with Brotli in the zlib library. The underlying Brotli dependency

already supports this and zstd exposes something similar.

This follows the zstd approach for using a custom dictionary but

for Brotli.
Fixes: #52250

PR-URL: #61763

Reviewed-By: Anna Henningsen <anna@addaleax.net>

Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Reviewed-By: James M Snell <jasnell@gmail.com>

Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
[detached HEAD 0b291ff59d] zlib: add support for brotli compression dictionary

Author: Andy Weiss <andy.weiss@reddit.com>

Date: Tue Feb 10 10:45:22 2026 -0500

3 files changed, 168 insertions(+), 11 deletions(-)

create mode 100644 test/parallel/test-zlib-brotli-dictionary.js

Rebasing (3/6)

Rebasing (4/6)

Executing: git node land --amend --yes

--------------------------------- New Message ----------------------------------

Fix lint, convert to r-value ref instead of string_view, add tests
PR-URL: #61763

Fixes: #52250

Reviewed-By: Anna Henningsen <anna@addaleax.net>

Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Reviewed-By: James M Snell <jasnell@gmail.com>

Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
[detached HEAD 5edccb22a4] Fix lint, convert to r-value ref instead of string_view, add tests

Author: Andy Weiss <andy.weiss@reddit.com>

Date: Wed Feb 11 11:46:32 2026 -0500

3 files changed, 84 insertions(+), 24 deletions(-)

Rebasing (5/6)

Rebasing (6/6)

Executing: git node land --amend --yes

--------------------------------- New Message ----------------------------------

Actually fix the lint
PR-URL: #61763

Fixes: #52250

Reviewed-By: Anna Henningsen <anna@addaleax.net>

Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Reviewed-By: James M Snell <jasnell@gmail.com>

Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
[detached HEAD 12eff1e7c3] Actually fix the lint

Author: Andy Weiss <andy.weiss@reddit.com>

Date: Thu Feb 12 08:59:07 2026 -0500

1 file changed, 12 insertions(+), 11 deletions(-)

Successfully rebased and updated refs/heads/main.
ℹ  Add commit-queue-squash label to land the PR as one commit, or commit-queue-rebase to land as separate commits.

https://github.com/nodejs/node/actions/runs/21993102795

[nodejs-github-bot]

Landed in 8f613ee