Field API: Validation

[oandregal]

What

This is a tracking issue to break down the work on implementing validation in the Field API.

See related iteration issue that tracks improvements to the DataViews and DataForm components planned for WordPress 6.9 and the overview issues for DataViews #55083 and DataForm #59745.

Goals

Support a number of general validation rules leveraging the HTML standard. If/when we introduce domain-specific types (e.g., slug), that would also support domain-specific validation. For the 1st iteration, we want to implement general validation, while supporting domain-specific validation via the isValid.custom.

Support both sync and async custom validation. In progress: controlled, uncontrolled.

Status

• not planned: -
• need to be implemented: empty cell
• shipped: ✅

field types / validation rules	required	custom	pattern	min/max	elements[1]
array			-	-	#71194
boolean	✅	✅	-	-
date			-	range of dates
datetime			-	range of dates
email	✅	✅		max=maxlength, min unsupported
integer	✅	✅	-	controls the range of input
media	-	-	-	-	-
password (field type to be implemented)				controls the length of input (min=minlength, max=maxlength)
telephone	✅	✅		-
text	✅	✅		controls the length of input (min=minlength, max=maxlength)
url (field type to be implemented)				-

Notes:

• [1] The elements validation rule is something we have hardcoded in the custom function of some field types (example) and we aim to extract. In some contexts, the UI component would restrict already the inputs (e.g., via select component) but others would require to set elements: true to make it so (e.g., ValidatedFormTokenField for array).