What the home's "Continue watching" panel renders.
Entities do not cross this boundary: the panel needs three strings, a
locale-relative href and — only for a video — a duration to size its
progress bar against. Sending whole entities would ship the lesson body
and every field the panel ignores to the browser.
durationSeconds is null for a reading lesson, which is the panel's
signal to omit the progress indicator rather than draw it at zero.
What the home's "Continue watching" panel renders.
Entities do not cross this boundary: the panel needs three strings, a locale-relative href and — only for a video — a duration to size its progress bar against. Sending whole entities would ship the lesson body and every field the panel ignores to the browser.
durationSecondsisnullfor a reading lesson, which is the panel's signal to omit the progress indicator rather than draw it at zero.