Safari supports it. Chrome had it ready, behind a feature flag. It was then dumped for FUDdy reasons centered around user concerns that turned out not to be war

Safari supports it. Chrome had it ready, behind a feature flag. It was then dumped for FUDdy reasons centered around user concerns that turned out not to be warranted (Safari has proper tail calls per the ES6 spec, and no one complains about it). The truth is that it would have been very expensive for MS to add it to Edge (which was built around incompatible calling conventions), and that cross-realm tail calls (calling into code from another I frame) would be hard to implement in Firefox. Now that Edge switched to Chromium, the only problem left is with FF. It could be spec’ed around, but the consensus in the TC-39 isn’t there anymore :-(