does not conform to the required format. The format is "yyyy-MM-ddThh:mm" followed by optional ":ss" or ":ss.SSS".
export function toDatetimeLocal(){
const date = new Date(),
ten = (i)=> ((i < 10 ? '0' : '') + i ),
YYYY = date.getFullYear(),
MTH = ten(date.getMonth() + 1),
DAY = ten(date.getDate()),
HH = ten(date.getHours()),
MM = ten(date.getMinutes()),
SS = ten(date.getSeconds())
// MS = ten(date.getMilliseconds())
return `${YYYY}-${MTH}-${DAY}T${HH}:${MM}:${SS}`
}