WordPress: add class to LI and A elements output by wp_nav_menu()

tps-nav-menu-customization.php

<?php
// Add class to A element of .primary-menu
function tps_primary_menu_anchor_class($item_output, $item, $depth, $args) {
    $item_output = preg_replace('/<a /', '<a class="nav-link" ', $item_output, 1);
    return $item_output;
}
add_filter('walker_nav_menu_start_el', 'tps_primary_menu_anchor_class', 10, 4);

// Add class to LI element of .primary-menu
function tps_primary_menu_li_class($objects, $args) {
    foreach($objects as $key => $item) {
      $objects[$key]->classes[] = 'nav-item';
    }
    return $objects;
}
add_filter('wp_nav_menu_objects', 'tps_primary_menu_li_class', 10, 2);
?>