gantt: today {value} is not a date or a day number; no today line is drawn.

Warnings reference › gantt.today:*

Identifier

gantt.today:*

Raised by

Gantt

Since

1.52.0

What happened

The today render option could not be read as a date or a day number, so the today marker is omitted from the timeline. Everything else draws normally, which is why the option is named rather than dropped without a word.

The fix

Pass a Date, an ISO date string, or a plan day number. Omit the option entirely if no marker is wanted.

The smallest fix

gantt.mount(el, { today: new Date() });

Reference

Covered in full at the API reference.