How to format ZF2 DateSelect "day" element to 2 digits? - zend-framework2

Question

I am wanting to do a date of birth composite drop-down for date of birth (i.e. three drop-downs - one for day, one for month, one for year). Helpfully, ZF2 comes with this element built in, called DateSelect
Here is how I am adding it to the form:
$this->add([
'name' => 'date_of_birth',
'type' => 'DateSelect',
'attributes' => [
'required' => true,
'value' => date('Y-m-d', strtotime('18 years ago')),
],
'options' => [
'label' => 'Date of Birth',
'max_year' => date('Y', strtotime('18 years ago')),
],
]);
To render the form I am doing:
echo $this->form($form);
Anyway, the day element is being rendered in j format (i.e. day of the month without leading zeros 1 to 31).
How do I tell the element to render the day in d format (i.e. day of the month, 2 digits with leading zeros 01 to 31)?

Answer 1

I have check source code from Zend\Form\Element\DateSelect and it's view helper Zend\Form\View\Helper\FormDateSelect. The rendering date is on view helper, but it didn't use date('j'). It use IntlDateFormatter to format date, and it will output date format based on locale date format pattern given.
https://github.com/zendframework/zend-form/blob/release-2.2.0/src/View/Helper/FormDateSelect.php#L90
So, the solution we should pass the locale date format that use two digits day (dd). For country date format list, can be check here
https://en.wikipedia.org/wiki/Date_format_by_country
Based on the date format on list above, India use DD-MM-YY as date format. we can use this locale to get two digit day format,.
So, please use this on your view helper
echo $this->formDateSelect($form->get('date_of_birth'), IntlDateFormatter::MEDIUM, 'en_IN');

Answer 2

The view helper Zend\Form\View\Helper\FormDateSelect has a function getPattern that generates the patten by using the IntlDateFormatter class:
$intl = new IntlDateFormatter($this->getLocale(), $this->dateType, IntlDateFormatter::NONE);
$this->pattern = $intl->getPattern();
There did not appear to be any method of setting a pattern at element level, so I have extended this view helper allowing me to specify my own pattern:
<?php
namespace RPK\Form\View\Helper;
use Zend\Form\View\Helper\FormDateSelect as ZendFormDateSelect;
class FormDateSelect extends ZendFormDateSelect
{
/**
* Parse the pattern
*
* #param bool $renderDelimiters
* #return array
*/
protected function parsePattern($renderDelimiters = true)
{
//Replace `day` value of "d" with "dd"
$pattern = parent::parsePattern($renderDelimiters);
if($pattern['day'] === 'd') {
$pattern['day'] = 'dd';
}
return $pattern;
}
}
Very basically, this takes the returned pattern array (['day'=>'d', 'month' => 'MMMM', 'year' => 'yyyy']), checks if the value of day is a single letter "d" and, if so, replaces it with a double-d.