Validation

Validation runs on the result, so it behaves identically whether the number was typed, computed from a formula, scrubbed or stepped. It also runs on the live draft, so the indicator you see while typing is exactly what commit will do.

build:

Type -5 into the first two and compare. Try 2.5 and 500 in the last one.

Defaults are CAD-friendly

Prop	Default	Effect
min	0	Positive-only unless allowNegative
max	9999999	Sane ceiling for dimensions
allowNegative	false	Permit values below zero
integerOnly	false	Reject fractional results
validate	—	(value) => true | string

Negatives

The value is floored at 0 however it arrives — typed, pasted, scrubbed, arrow-tapped or keyboard-nudged. Attempts to go lower clamp and fire onClamp.

min interacts deliberately: while allowNegative is false, a negative min is ignored and treated as 0, so the flag is the single switch governing sign.

Config	Effective floor
(nothing)	0
min={10}	10
min={-50}	0 — negative min ignored
allowNegative	unbounded below
allowNegative min={-50}	-50

Custom rules

Return true to accept, or a message to reject. The message shows on the revert button's tooltip.

<DimensionInput
  valueMm={v}
  onChangeMm={setV}
  unit={unit}
  integerOnly
  validate={(n) => (n % 5 === 0 ? true : 'Must be a multiple of 5')}
/>

Rejected entries

A rejected value is never silently discarded. The text you typed stays on screen, the border turns red, and a small revert button restores the last good number — or call ref.current.revert().

const ref = useRef<ScrollComponentHandle>(null);

ref.current?.revert();
ref.current?.stepUp();
ref.current?.focus();