Why are Loop dependent functions used outside of Loop?

Question

WordPress

I'm new to Wordpress, getting familiar with Loop. I got to the variables / functions that work inside the loop. For example, get_permalink() without an ID attribute should be used inside a loop. In the code of the theme, formed using underscores, there is a content.php template, where there is such a piece

if ( is_singular() ) :
      the_title( '<h1 class="entry-title">', '</h1>' );
    else :
      the_title( '<h2 class="entry-title"><a href="' . esc_url( get_permalink() ) . '" rel="bookmark">', '</a></h2>' );
    endif;

It would seem that outside the loop, then get_permalink() should not work without an attribute, but it does. Why?

Answer 1

Because WordPress really likes to use global variables. The function get_permalink()takes an object or post_id as an argument $post(i.e., you can pass the id of any post or any object $postin principle), and by default this argument refers to the global $postone, which is why it works outside the loop and without an argument.
These functions are meant to be used outside of the loop because that's often what's needed.