Currently, web developers can use PerformanceObserver with buffered flag to listen to past and future performance entries about their site. However, past entries need to be stored, and there is a buffer size limit. The hasDroppedEntry boolean property helps developers know if they may have lost an entry due to this storage being full. It's set to true when there exists an entryType being observed for which an entry got dropped from the buffer due to such buffer being full.


Specification link

Specification being incubated in a Community Group

Status in Chromium


No active development (tracking bug)

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

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Last updated on 2020-11-25