How can I recursively create a UL/LI's from JSON data - multiple layers deep

Question

I am trying to use use the following JSON data to create the following similar structure in a recursive inner function with not much luck, really need some help and so if anyone can assist please do. Thank you in advance.

<ul>
    <li></li>
    <li>
        <a href=""></a>
        <div>
            <ul>
                <li>
                    <a href=""></a>
                    <div>
                         ....etc
                    </div>
                </li>
            </ul>
        </div>
    </li>
</ul>

the JSON data I am using is as follows:

    var JSON = {
    menu: [
        {id: '0',sub: [
            {name: 'lorem ipsum 0-0',link: '0-0', sub: null},
            {name: 'lorem ipsum 0-1',link: '0-1', sub: null},
            {name: 'lorem ipsum 0-2',link: '0-2', sub: null}
            ]
        },
        {id: '1',sub: null},
        {id: '2',sub: [
            {name: 'lorem ipsum 2-0',link: '2-0', sub: null},
            {name: 'lorem ipsum 2-1',link: '2-1', sub: null},
            {name: 'lorem ipsum 2-2',link: '2-2', sub: [
                {name: 'lorem ipsum 2-2-0',link: '2-2-0', sub: null},
                {name: 'lorem ipsum 2-2-1',link: '2-2-1', sub: null},
                {name: 'lorem ipsum 2-2-2',link: '2-2-2', sub: null},
                {name: 'lorem ipsum 2-2-3',link: '2-2-3', sub: null},
                {name: 'lorem ipsum 2-2-4',link: '2-2-4', sub: null},
                {name: 'lorem ipsum 2-2-5',link: '2-2-5', sub: null},
                {name: 'lorem ipsum 2-2-6',link: '2-2-6', sub: null}
            ]},
            {name: 'lorem ipsum 2-3',link: '2-3', sub: null},
            {name: 'lorem ipsum 2-4',link: '2-4', sub: null},
            {name: 'lorem ipsum 2-5',link: '2-5', sub: null}
            ]
        },
        {id: '3',sub: null}
    ]
}

and the code I have created (incomplete, this is the brain teaser I need help on) is:

$(function(){

    $.fn.dropdown = function(settings){
        var that = this;
        var settings = $.extend({}, $.fn.dropdown.defaults, settings);
        var methods = {
            isArray: function(o){
                return Object.prototype.toString.call(o) === '[object Array]';
            },
            createDropdownCode: function(arr){
                var menu = arr.menu;
                var html = null;
                var menusort = function(menu){
                    html = that;

                    that.find("li").each(function(idx){

                        var menuList = menu[idx].sub;
                        var baseContainer = $(this);
                        var count = -1;

                        var subsort = (function(){

                            count += 1;

                            return function(submenu, pb){

                                var subblock;
                                subblock = $("<div />").append('<ul />');

                                if(methods.isArray(submenu)){

                                    for(var i=0;i<submenu.length;i++){

                                        var l = $("<li />").append("<a href='"+ submenu[i].link +"'>"+ submenu[i].name +"</a>");

                                        subblock.find('ul').append(l);

                                        if(pb !== undefined && i == submenu.length-1){
                                            pb.append(subblock)
                                        }

                                        if(methods.isArray(submenu[i].sub)){
                                            subsort(submenu[i].sub, subblock.find('ul li').eq(i));
                                        }

                                    }
                                }
                            }
                        })()
                        subsort(menuList)
                    })
                }
                menusort(menu);
                return null; //html !== null ? html.html() : null;
            },
            init: function(){

                // filter through json
                // create the div=>ul=>li
                if(settings.jsonData === undefined || settings.jsonData === null){
                    console.warn('No JSON Data passed')
                    return;
                }else{
                    if(!methods.isArray(settings.jsonData.menu)){
                        console.warn('No JSON Data passed')
                        return; // error, no data!
                    }
                }


                //var html = methods.createBlock(settings.jsonData.menu[0].sub);
                var html = methods.createDropdownCode(settings.jsonData);
                //console.log(html) 
            }
        }

        methods.init();

        return that;

    }

    $.fn.dropdown.defaults = {
        jsonData: null
    }

})

$('#menu').dropdown({
    jsonData: JSON
});

integrated code used, thanks to the individual that gave a close enough answer - Although will study the others.

$.fn.dropdown = function(settings){

    var that = this;
    var settings = $.extend({}, $.fn.dropdown.defaults, settings);

    var methods = {
        createDropDownCode: function(arr){

            // loop through li's of primary menu
            that.find("li").each(function(idx){

                $(this).append( menusort(arr.menu[idx].sub) );

                function menusort(data){
                    if(data !== null)   
                        var html = "<div><ul>";

                    for(item in data){
                        html += "<li>";
                        if(typeof(data[item].sub) === 'object'){
                            html += "<a href='" + data[item].link + "'>" + data[item].name + "</a>";
                            if($.isArray(data[item].sub))
                                html += menusort(data[item].sub);
                        }
                        html += "</li>"
                    }
                    if(data !== null)
                        html += "</ul></div>";
                    return html;
                }
            })
        },
        init: function(){
            var html = methods.createDropDownCode(settings.jsonData);

        }
    }

    methods.init();

}

Answer 1

You can try this recursive function I've just coded:

function buildList(data, isSub){
    var html = (isSub)?'<div>':''; // Wrap with div if true
    html += '<ul>';
    for(item in data){
        html += '<li>';
        if(typeof(data[item].sub) === 'object'){ // An array will return 'object'
            if(isSub){
                html += '<a href="' + data[item].link + '">' + data[item].name + '</a>';
            } else {
                html += data[item].id; // Submenu found, but top level list item.
            }
            html += buildList(data[item].sub, true); // Submenu found. Calling recursively same method (and wrapping it in a div)
        } else {
            html += data[item].id // No submenu
        }
        html += '</li>';
    }
    html += '</ul>';
    html += (isSub)?'</div>':'';
    return html;
}

It returns the html for the menu, so use it like that: var html = buildList(JSON.menu, false);

I believe it is faster because it's in pure JavaScript, and it doesn't create text nodes or DOM elements for every iteration. Just call .innerHTML or $('...').html() at the end when you're done instead of adding HTML immediately for every menu.

JSFiddled: http://jsfiddle.net/remibreton/csQL8/

Answer 2

Make two functions makeUL and makeLI. makeUL calls makeLI on each element, and makeLI calls makeUL if there's sub elements:

function makeUL(lst) {
    ...
    $(lst).each(function() { html.push(makeLI(this)) });
    ...
    return html.join("\n");
}

function makeLI(elem) {
    ...
    if (elem.sub)
        html.push('<div>' + makeUL(elem.sub) + '</div>');
    ...
    return html.join("\n");
}

http://jsfiddle.net/BvDW3/

Needs to be adapted to your needs, but you got the idea.

Answer 3

Pure ES6

var foo=(arg)=>
`<ul>
${arg.map(elem=>
    elem.sub?
        `<li>${foo(elem.sub)}</li>`
        :`<li>${elem.name}</li>`
    ).join('')}
</ul>`

JSON example

   var bar = [
  {
    name: 'Home'
  }, {
    name: 'About'
  }, {
    name: 'Portfolio'
  }, {
    name: 'Blog'
  }, {
    name: 'Contacts'
  }, {
    name: 'Features',
    sub: [
      {
        name: 'Multipage'
      }, {
        name: 'Options',
        sub: [
          {
            name: 'General'
          }, {
            name: 'Sidebars'
          }, {
            name: 'Fonts'
          }, {
            name: 'Socials'
          }
        ]
      }, {
        name: 'Page'
      }, {
        name: 'FAQ'
      }
    ]
  }
]
var result=foo(bar)

Your 'result' will be valid HTML