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.