Tawanda Moyo

engineer & writer

projects / standards & open source

SpiderMonkey - TC39 Joint Iteration

Two patches landed in Firefox 133 - the nightly-gated preference controlling the TC39 Joint Iteration proposal, and the placeholder implementation for Iterator.zip.

bugzilla.mozilla.org

What this is

Contributed to Firefox’s JavaScript engine through Outreachy, mentored by Dan Minor at Mozilla.

I landed the nightly-only preference that gates the TC39 Joint Iteration proposal (javascript.options.experimental.joint_iteration) - the switch the rest of the proposal builds on, and a blocker for two dependent bugs - and the placeholder implementation for Iterator.zip : an #ifdef NIGHTLY_BUILD guard in Iterator.js, registered as a static method and conditionally removed when the pref is off.

Both patches shipped in Firefox 133.

Important lessons on working on a massive codebase with thousands of contributors.