ACF Checkbox loop not displaying all posts - wordpress

Question

I've created a shortcode that displays a loop, in which it SHOULD display all posts in 'products', that have the checkbox selected as value 'yes'. However, it's not displaying all the posts, it's only displaying one.
Here's my code:
function featured_products() {
$args = array(
'posts_per_page' => -1,
'post_type' => 'products',
'meta_query' => array(
array(
'key' => 'home_featured',
'value' => '1',
'compare' => 'LIKE'
),
),
);
$the_query = new WP_Query( $args );
if ( $the_query->have_posts() ) {
while ( $the_query->have_posts() ) {
$the_query->the_post();
$output = '<p>' . get_the_title() . '</p>';
}
echo '</ul>';
wp_reset_postdata();
} else {
$output = "<p>There aren't any products to display.</p>";
}
return $output;
}
add_shortcode('featured_products', 'featured_products');
What am I doing wrong here in terms of displaying more than one post?
This is what my custom field setup looks like:
Now I'm having trouble with the output. For some reason, the loop is displaying right at the top of the page's content container:
function featured_products() {
$args = array(
'posts_per_page' => 10,
'post_type' => 'products',
'meta_query' => array(
array(
'key' => 'home_featured',
'value' => '1',
'compare' => 'LIKE'
),
),
);
$output .= '<div class="products">';
$the_query = new WP_Query( $args );
if ( $the_query->have_posts() ) {
while ( $the_query->have_posts() ) {
$the_query->the_post();
$output .= '<div class="col-eq-height col-md-6" style="margin-bottom:30px;">';
$output .= '<div class="product">';
$output .= '<div id="thumbnail"><a href="' . get_the_permalink() . '">';
$output .= get_the_post_thumbnail();
$output .= '</a></div>';
$output .= '<div id="content">';
$output .= '<p id="title">' . get_the_title() . '</p>';
echo '<p>' . the_field('product_price_exc_vat') . '</p>';
$output .= '</div>';
$output .= '</div>';
$output .= '</div>';
}
wp_reset_postdata();
} else {
$output .= "<p>There aren't any products to display.</p>";
}
$output .= '</div>';
return $output;
}
add_shortcode('featured_products', 'featured_products');

Answer 1

The problem here is, that $output is being overwritten every time it iterates.
Meaning that you will only get the last title.
putting a dot infront of the = sign, will gather it instead of overwriting it.
So to sum up -
Initiate
$output ="";
Outside the loop, and then push it together inside your while
$output .="whateverHtml".$variable."whateverHtml";