Posts of current month - Filter extension

functions.php

<?php
// Filter extension: "Show only post from the current month and the current year"

/**
 * Adds a checkbox to the My settings panel which can be checked/unchecked the 'Posts of current month' filter/hook
 *
 * @param  widget, instance
 * @return adds a ckeckbox to the form()
 */
function cpwp_add_extensions_panel( $widget, $instance ) {

	$instance = wp_parse_args( ( array ) $instance, array(
		'use_current_month_filter' => ''
	) );
	$use_current_month_filter = $instance['use_current_month_filter'];
		
	echo '<p>'.
			'<label for="'.$widget->get_field_id('use_current_month_filter').'">'.
				'<input type="checkbox" class="checkbox" id="'.$widget->get_field_id('use_current_month_filter').'" name="'.$widget->get_field_name('use_current_month_filter').'" ';
	echo			checked( (bool) $instance["use_current_month_filter"], true ).' />';
	echo		_e( 'Use current month filter extention','categorypostspro' ).
			'</label>'.
		'</p>';
}
add_filter('cpwp_bottom_mysettings_panel','cpwp_add_extensions_panel', 10, 2);


/**
 * Adds a filter/hook to get only post from the current month and year.
 *
 * @param  query, widget, instance
 * @return query
 */
function cpwp_get_posts_of_current_month ( $query, $widget, $instance ) {
	if( isset($instance['use_current_month_filter']) && $instance['use_current_month_filter'] ) {
		$query = array_merge( $query, array( 'date_query' => array(
				array(
				 'year'  => date('Y'),
				 'month' => date('n') )
				)
			)	
		);
	}	
	return $query;
}
add_filter( 'cpwp_query_args', 'cpwp_get_posts_of_current_month', 10, 3 );