Iterator Sequencing

for Stage 4

Michael Ficarra • TC39 • November 2025

Implementations

JSC

• 2024-10: implemented
• 2024-11: available (flagged) in Safari Technology Preview 208
• 2025-03: available (flagged) in Safari 18.4

V8

• ¯\_(ツ)_/¯

SpiderMonkey

• 2024-11: implemented
• 2024-11: available (flagged) in nightlies from 135+
• 2025-02: available (flagged) in stable
• 2025-10: intent to ship
• 2025-11: available (unflagged) in nightlies from 147+
• 2026-01: planned availability (unflagged) in stable

Stage 4?