defaultKinds

The built-in kinds, by name: string, number, boolean, date, array, file, object and none.

const kinds = defaultKinds

Explanation

Each says what counts as empty, and adds a required check where emptiness isn't enough:

Kind	Empty	Required
string	undefined, null or ''	not empty
number	undefined, null, '' or NaN	not empty
boolean	undefined or null	true, like a ticked box
date	undefined, null or ''	not empty
array	undefined, null or []	at least one item
file	undefined or null	not empty
object	undefined or null	not empty
none	always: a display element has no value	never checked

Your own kinds merge over them by name, with the kinds option.

Related

Types

• KindDef
• ValueKind