13: Sanitize field values

You can provide a sanitization callback function for your field's value. For example, you may want to ensure that the value entered by a user for your field is returned as a number no matter what they enter.

To do that, first define your sanitization callback function that returns the sanitized value:

function sanitize_number( $value ) {
  return absint( $value );
}

Then specify that function in your field config using the sanitize parameter:

'font_size' => array(
  'type'          => 'unit',
  'label'         => 'Font Size',
  'description'   => 'px',
  'sanitize'    => 'sanitize_number',
),