How to Apply Custom Validator to FreedomUI List?

You can register/apply validators to fields on the page using these instructions: https://academy.creatio.com/docs/developer/front_end_development_freedo…



But how can you apply a validator to an editable field within a list or a "collection" data source?



If you try to add a validator to the field as normal e.g.

 

viewModelConfigDiff: /**SCHEMA_VIEW_MODEL_CONFIG_DIFF*/[
{
	"operation": "merge",
	"path": [
		"attributes"
	],
	"values": {
		"ContactCommunicationOptionsItems": {
		"isCollection": true,
		"modelConfig": {
			"path": "ContactCommunicationOptionsDS",
			"sortingConfig": {
				"default": [
					{
						"columnName": "CreatedOn",
						"direction": "asc"
					}
				]
			}
		},
		"viewModelConfig": {
			"attributes": {
				"ContactCommunicationOptionsDS_CreatedOn": {
					"modelConfig": {
						"path": "ContactCommunicationOptionsDS.CreatedOn"
					}
				},
				"ContactCommunicationOptionsDS_Number": {
					"modelConfig": {
						"path": "ContactCommunicationOptionsDS.Number"
					},
					"validators": {
						"TESTValidator": {
							"type": "q.TestValidator",
							"params": {}
						}
					}
				},
				.....

An error in the console is displayed: Error: Validator 'q.TestValidator' was not registered. 



How do I "register" a validator to work within a list?