Added the possibility to split date range values

[RubenMartins]

This will allow to query more effectively between dates.

Props to @rasmustaarnby #9

Can you review this @jtsternberg please?

[RubenMartins]

Some notes:

1. Should the split_date_range arg be set to true as default?
2. Should be removed the default meta_key and meta_value in DB which is in json when the split_date_range is set to true?

Let me know your thoughts.

[tw2113]

I can merge when @jtsternberg is approving with what he sees for this.

[RubenMartins]

Thank you @jtsternberg for the quick review and comments. When possible can you give it another review? Should be ready to ship with this last commits @tw2113

Again thank you both for the quick reply

[RubenMartins]

This isn't a repo I have access to, but here's a quick review.

1. Should the split_date_range arg be set to true as default?
2. Should be removed the default meta_key and meta_value in DB which is in json when the split_date_range is set to true?

1. no, because backwards-compatibility should be maintained
2. Probably not a bad idea

Unfortunately I can't remove the 2. as the daterangepicker js is using it to populate the field value on load.

[RubenMartins]

@jtsternberg this is not correct, can you please let me know how to accomplish the class call to CMB2_Fiel

Any updates on this please?

[jtsternberg]

@RubenMartins try this:

	function save_split_date_range( $field_id, $updated, $action, $cmb2_field ) {
		if ( ! $updated || 'repeatable' === $action || ! $cmb2_field->args( 'split_date_range' ) ) {
			return;
		}

		$start_field = $cmb2_field->get_field_clone( array(
			'id' => $field_id . '_start',
		) );

		$end_field = $cmb2_field->get_field_clone( array(
			'id' => $field_id . '_end',
		) );

		if ( $action === 'removed' ) {
			$start_field->remove_data();
			$end_field->remove_data();

			return;
		}

		$value = json_decode( $cmb2_field->value, true );

		if ( is_array( $value ) ) {
			$value = array_map( 'sanitize_text_field', $value );

			$start_field->update_data( $value['start'] );
			$end_field->update_data( $value['end'] );
		}
	}

[RubenMartins]

@RubenMartins try this:

	function save_split_date_range( $field_id, $updated, $action, $cmb2_field ) {
		if ( ! $updated || 'repeatable' === $action || ! $cmb2_field->args( 'split_date_range' ) ) {
			return;
		}

		$start_field = $cmb2_field->get_field_clone( array(
			'id' => $field_id . '_start',
		) );

		$end_field = $cmb2_field->get_field_clone( array(
			'id' => $field_id . '_end',
		) );

		if ( $action === 'removed' ) {
			$start_field->remove_data();
			$end_field->remove_data();

			return;
		}

		$value = json_decode( $cmb2_field->value, true );

		if ( is_array( $value ) ) {
			$value = array_map( 'sanitize_text_field', $value );

			$start_field->update_data( $value['start'] );
			$end_field->update_data( $value['end'] );
		}
	}

Thank you @jtsternberg this is way better. When possible please review the pr again.