The purpose of the Callback constraint is to create completely custom validation rules. This process works by specifying one or more callback methods, each of which will be called during the validation process.
The callback function will be executed with empty values, so developer should take care about such checks.
type: function
The callback method itself. It should return TRUE or FALSE value based on provided logic.
Callback parameters:
| Parameter | Description |
|---|---|
| value | The current value |
| options | Object that contains current form and custom options. See form methods description |
Options example:
{
'form': {}, // current Form object
'field': {}, // current filed options from Form.add()
// ...
'prefix': 'custom options from Form.validate()'
}type: string default: This value is not a valid.
| Parameter | Description |
|---|---|
| {{ value }} | The current (invalid) value |