I have this Jquery and trying to convert to pure JS. Can someone help?

    (function($) {
    $(".comments-content > ol > .comment").each(function() {
        var str = $(this).children(".comment-block").find(".comment-header > .name > span").text();
        $(this).find(&quot;.comment-avatar&quot;).append(&quot;<span>&quot; + str.charAt(0) + &quot;</span>&quot;);
    });  
    })(jQuery);

So far, I have reached here:

var elements = document.querySelectorAll(".comments-content > ol > .comment");
Array.prototype.forEach.call(elements, function(){
let str = this.children(".comment-block").find(".comment-header > .name > span").innerText;
        this.querySelectorAll(&quot;.comment-avatar&quot;).append(&quot;<span>&quot; + &quot; str.charAt(0) &quot; + &quot;</span>&quot;);
});