Group list items in sub-lists based on data attribute

Question

I want to add <li>from one <ul>to another <ul>, created on the fly. I want to group list items into new sub-lists based on their attribute data-group.

<ul id="sortable1">
    <li data-group="A">test</li>
    <li data-group="A">test1</li>
    <li data-group="B">test2</li>
    <li data-group="B">test3</li>
    <li data-group="C">test4</li>
</ul>

Basically, I try to skip this list and grab everything <li>from each group, and then move it to another <ul>.

This is what I have so far, but I am not getting the expected results. I have done this in Excel in the past, but cannot get it to work with jQuery.

var listItems = $("#sortable1").children("li");
listItems.each(function (idx, li) {
    var product = $(li);
    //grab current li
    var str = $(this).text();

    if (idx > 0) {
        //append li
        str += str;
        if ($(this).data("group") != $(this).prev().data("group")) {
            //I should be getting  test and test1. 
            //but alert is only giving test1 test1. 

            alert(str);
            //need to break into groups
            //do something with groups
        }
    }
});

Answer 1

How about something like this:

$(function() {
    var sortable = $("#sortable1"),
        content = $("#content");

    var groups = [];
    sortable.find("li").each(function() { 
        var group = $(this).data("group");
        if($.inArray(group, groups) === -1) {
            groups.push(group);
        }
    });
    
    groups.forEach(function(group) { 
        var liElements = sortable.find("li[data-group='" + group + "']"),
            groupUl = $("<ul>").append(liElements);
        content.append(groupUl);
    });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<ul id="sortable1">
    <li data-group="A">test</li>
    <li data-group="A">test1</li>
    <li data-group="B">test2</li>
    <li data-group="B">test3</li>
    <li data-group="C">test4</li>
</ul>

<div id="content">    
</div>

Run codeHide result

I hope I didn’t get you wrong.