How to rewrite default php code to a valid echo line output?

I am new to PHP and for the development of a WordPress theme I need to re-write the following line of php/html code so that I can use it in my functions.php. I found out that I would need to rewrite it as an “echo” call, but I am always getting an error because my syntax is wrong.

This is the line we’re talking about:

<div <?php post_class( 'brick_item ' . $termString ) ?> onclick="location.href='<?php the_permalink(); ?>'">

I’ve tried several times, e.g.

echo '<div class="'. post_class("brick_item" . $termString); .'" onclick=location.href="'. the_permalink() .'">';

but I am doing something wrong in encapsulating things I guess.

EDIT: As requested, the part of the functions.php

    function get_latest_posts() {
        
        echo '<div class="latest-posts">';
            echo '<div class="brick_list">';

                $args = array(
                    post_type => 'post',
                    cat => '-3,-10',
                    posts_per_page => 3
                );

                $latestposts_query = new WP_Query($args);

                if ( $latestposts_query->have_posts() ) : while ( $latestposts_query->have_posts() ) : $latestposts_query->the_post(); 
                    
                    echo '<div '. post_class( $termString ) .' onclick=location.href='. the_permalink() .'>';

                endwhile; else :

                    get_template_part('template_parts/content','error');

                endif; 
                wp_reset_postdata();

            echo '</div>';
        echo '</div>';
    }
    add_shortcode( 'get_latest_posts', 'get_latest_posts' );

Answer

There is a semicolon in the middle of your line

echo '<div class="'. post_class("brick_item" . $termString); .'" onclick=location.href="'. the_permalink() .'">';

should be

echo '<div class="'. post_class("brick_item" . $termString) .'" onclick=location.href="'. the_permalink() .'">';

semicolons signify end of line in php, thus your code did first execute

echo '<div class="'. post_class("brick_item" . $termString);

which is fine, but only half of what you want. Then php tries executing

.'" onclick=location.href="'. the_permalink() .'">';

but doesn’t know what to do with a dot at the start of the line. Dot means append string before to string after, but there is nothing before, so it’s a compile error. You can also just add another echo to the second line instead of the dot

echo '" onclick=location.href="'. the_permalink() .'">';