newsupernova/app/code/Mageplaza/LayeredNavigation/view/frontend/templates/view.phtml

<?php if ($block->canShowBlock()): ?>
    <div class="block filter" id="layered-filter-block" data-mage-init='{"collapsible":{"openedState": "active", "collapsible": true, "active": false, "collateral": { "openedState": "filter-active", "element": "body" } }}'>
        <?php $filtered = count($block->getLayer()->getState()->getFilters()) ?>
        <div class="block-title filter-title" data-count="<?php /* @escapeNotVerified */ echo $filtered; ?>">
            <strong data-role="title"><?php /* @escapeNotVerified */ echo __('Shop By') ?></strong>
        </div>
        <div class="block-content filter-content">
            <?php echo $block->getChildHtml('state') ?>

            <?php if ($block->getLayer()->getState()->getFilters()): ?>
                <div class="block-actions filter-actions">
                    <a href="<?php /* @escapeNotVerified */ echo $block->getClearUrl() ?>" class="action clear filter-clear"><span><?php /* @escapeNotVerified */ echo __('Clear All') ?></span></a>
                </div>
            <?php endif; ?>
            <?php $wrapOptions = false; $activeKey = 0; $activeArray = []; ?>
            <?php foreach ($block->getFilters() as $key => $filter): ?>
                <?php if ($filter->getItemsCount()): ?>
                    <?php if (!$wrapOptions): ?>
                        <strong role="heading" aria-level="2" class="block-subtitle filter-subtitle"><?php /* @escapeNotVerified */ echo __('Shopping Options') ?></strong>
                        <div class="filter-options" id="narrow-by-list" data-role="content">
                    <?php  $wrapOptions = true; endif; ?>
                    <div data-role="collapsible" class="filter-options-item">
                        <div data-role="title" class="filter-options-title"><?php /* @escapeNotVerified */ echo __($filter->getName()) ?></div>
                        <div data-role="content" class="filter-options-content"><?php /* @escapeNotVerified */ echo $block->getChildBlock('renderer')->render($filter); ?></div>
                    </div>
                    <?php
                        if($block->getRequest()->getParam($filter->getRequestVar())){
                            $activeArray[] = $activeKey;
                        }
                        $activeKey++;
                    ?>
                <?php endif; ?>
            <?php endforeach; ?>
            <?php if ($wrapOptions): ?>
                </div>
				<script type="text/x-magento-init">
					{
						"#narrow-by-list": {
							"accordion": {
								"openedState": "active",
								"collapsible": true,
								"active": <?php echo sizeof($activeArray) ? $this->helper('Magento\Framework\Json\Helper\Data')->jsonEncode($activeArray) : 'false' ?>,
								"multipleCollapsible": true
							},
							"Mageplaza_LayeredNavigation/js/layer": {}
						}
					}
				</script>
            <?php endif; ?>
            <div id="ln_overlay" class="ln_overlay">
                <img src="<?php /* @escapeNotVerified */ echo $block->getViewFileUrl('images/loader-1.gif'); ?>" alt="Loading...">
            </div>
        </div>
    </div>
<?php endif; ?>
<style type="text/css">
    .ln_overlay{
        background-color: #FFFFFF;
        height: 100%;
        left: 0;
        opacity: 0.5;
        filter: alpha(opacity = 50);
        position: absolute;
        top: 0;
        width: 100%;
        z-index: 555;
        display:none;
    }
    .ln_overlay img {
        top: 30%;left: 45%;display: block;position: absolute;
    }
</style>