Woocommerce - How to populate custom select field with stored values on checkout page?

Question

I have converted the postcode field in checkout to a dropdown field. Its working fine.

$fields['billing']['billing_postcode'] = array(
    'type' => 'select',
    'label'     => __('Locality - Postcode', 'woocommerce'),
    'placeholder'   => _x('Select a locality', 'placeholder', 'woocommerce'),
    'required'  => true,
    'class'     => array('form-row-first'),
    'clear'     => false
     ); 

This is getting updated in the db and values show on order invoice. Now how would I show the already stored value of postcode field as selected option in the checkout fields. For ex: How the name is auto populated for a registered customer based on his earlier order. I have tried a few functions, but no relief. Kindly advice somebody!

Answer 1

I just had a similar problem and solved it with a combination of PHP and jQuery.

If $stored_value is what you have pulled from the DB and #billing_postcode is the id of the select-tag:

<?php if ( !empty( $stored_value ) ) { ?>
<script type="text/javascript">
    jQuery(document).ready(function($) {
        $("select#billing_postcode").val( "<?php echo $stored_value; ?>" );
    });
</script>
<?php } ?>

I use this inside a function that I apply to the "woocommerce_checkout_fields" filter.

Update 1: After a little bit more research I found out that I can also just do this:

<?php if ( !empty( $stored_value ) ) {
$fields['billing']['billing_postcode']['default'] = $stored_value;
} ?>

Update 2:

In functions.php of my theme, I put it in like this:

<?php
// Hook in
add_filter( 'woocommerce_checkout_fields' , 'jsm_override_checkout_fields' );

function jsm_override_checkout_fields( $fields ) {

    $stored_value = "something pulled from the DB";

    if ( !empty( $stored_value ) ) {
    $fields['billing']['billing_postcode']['default'] = $stored_value;
    }

    return $fields;
} ?>