How to show Published date and/or Modified date

Question

My code is based on the underscores reference theme. I have a posted_on function as follows:

function example_posted_on() {
        $time_string = '<time class="entry-date published updated" datetime="%1$s">%2$s</time>';
        if ( get_the_time( 'U' ) !== get_the_modified_time( 'U' ) ) {
            $time_string = '<time class="entry-date published" datetime="%1$s">%2$s</time><time class="updated" datetime="%3$s">%4$s</time>';
        }

$time_string = sprintf( $time_string,
    esc_attr( get_the_date( 'c' ) ),
    esc_html( get_the_date() ),
    esc_attr( get_the_modified_date( 'c' ) ),
    esc_html( get_the_modified_date() )
);

    $posted_on = sprintf(
    ' %s',
    $time_string
);

echo '<span class="posted-on">' . $posted_on . '</span>';  //WPCS: XSS  OK.
}

The result is that example_posted_on() correctly displays only the published date. My questions are: Why does it get the modified date anyway? How is it possible to show the modified date in addition or instead the published date.

Answer 1

This function should be displaying both modified and published dates only if they differ.

    if ( get_the_time( 'U' ) !== get_the_modified_time( 'U' ) ) {
        $time_string = '<time class="entry-date published" datetime="%1$s">%2$s</time><time class="updated" datetime="%3$s">%4$s</time>';
    }

Dates are compared using timestamps and if they don't match the string format is set to two <time> tags otherwise it's just published date.