bs4navwalker

<nav class="navbar fixed-top navbar-expand-lg navbar-dark bg-fade">
	<a class="navbar-brand" href="<?php echo esc_url( home_url( '/' ) ); ?>">
	 <img src="<?php echo get_template_directory_uri(); ?>/images/travelracing01.png" width="30" height="30" class="d-inline-block align-middle" alt=""> <?php bloginfo('name'); ?>
 </a>

   <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#bs4navbar" aria-controls="bs4navbar" aria-expanded="false" aria-label="Toggle navigation">
     <span class="navbar-toggler-icon navbar-light"></span>
   </button>

   <?php
   wp_nav_menu([
     'menu'            => 'メインメニュー',
     'theme_location'  => 'main-menu',
     'container'       => 'div',
     'container_id'    => 'bs4navbar',
     'container_class' => 'collapse navbar-collapse',
     'menu_id'         => false,
     'menu_class'      => 'navbar-nav mr-auto',
     'depth'           => 2,
     'fallback_cb'     => 'bs4navwalker::fallback',
     'walker'          => new bs4navwalker()
   ]);
   ?>
	 <span class="collapse navbar-collapse" id="bs4navbar">
<form class="form-inline my-2 my-lg-0">
<input class="form-control mr-sm-2" type="search" placeholder="検索">
<button class="btn btn-outline-secondary my-2 my-sm-0" type="submit">検索</button>
</form>
</span>
</nav>