Hi! 👋
My name is YongSeok Jang
and I am a frontend engineer.

Based in Seoul, South Korea. 🇰🇷

• Jun2021 - Current (3+ years)
  드라마앤컴퍼니(Drama&Company) - 리멤버
  Web Frontend Engineer

• Feb2015 - Feb2022
  Dongguk University (동국대학교)
  Computer Science & Engineering, Food Science & Biotechnology

• April 2025
  React DevTools [link]
  • PR #32614 (+124/−3 LOC, merged)
  • Re-implemented Trace Updates overlay with the Popover API, making update highlights visible even over <dialog>/<popover>.
• April 2025
  React DevTools [link]
  • PR #32703 (+23/−3 LOC, under review)
  • Migrated Component Inspector overlay to the same Popover-based top-layer, unifying all DevTools overlays and fixing similar visibility issues.
• March 2025
  flow-typed [link]
  • PR #4607 merged: Added full DOM typings & tests for the new Popover API (+95 LOC).
  • Enables Flow users to adopt <popover> and ToggleEvent with static-type safety across all supported Flow versions.

YouTube Channel

Let's Connect

• twitter-x /
• github /
• linkedin /
• email /
• What should I add next?