gantt: level() is not available on a plan that maps `fields.start`, because leveling has to write a new start back and a field mapping only says how to READ one. Level the plan with its own `start` field, or apply the returned moves yourself.

Warnings reference › gantt-level-mapped-start

Identifier

gantt-level-mapped-start

Raised by

Gantt

Since

1.59.0

What happened

Resource levelling is the one operation that writes a task's start back - it delays tasks to free an over-allocated resource - and this plan maps start through fields. Writing the canonical start would leave the scheduler reading the mapped value and the leveller looping until it hit its iteration cap, so the call is refused outright and returns { ok: false, error: { code: 'mapped-start' } }.

The fix

Level a plan whose tasks carry their own start, or compute the moves elsewhere and apply them to your rows yourself.

Reference

Covered in full at the API reference.