fires when the scale is re-rendered in order to display all tasks completely
gantt.attachEvent("onScaleAdjusted", function(){
const min = gantt.getState().min_date;
const max = gantt.getState().max_date;
const to_str = gantt.templates.task_date;
return gantt.message(`Scale shows days from ${to_str(min)}
to ${to_str(max)}`);
});
Note, the event will fire only if the fit_tasks property is set to true.