在嵌套JavaScript数组中循环播放问题

Question

I am having issues looping through a nested JavaScript array and need some help. I am trying to return a set of list items with both the property name and the value, but it's returning as undefined. Any help would be much appreciated as this is an important project.

JavaScript

$.getJSON("item-data.json", function(results) {
        $.each(results.CatalogEntryView, function(index, item) {
            console.dir(item.ItemDescription[0].features);

            document.getElementById("productHighlightsList").innerHTML = item.ItemDescription[0].features.forEach(enumerateProperties)

function enumerateProperties(key, val)
        {
            return "<li>" + key + val + "</li>"
        }

        });
    });

The console output from console.dir(item.ItemDescription[0].features); can be seen below and shows the nested data structure I am trying to access:

Answer 1

Since you're using jQuery, you can just use each again for that nested array:

$.getJSON("item-data.json", function(results) {
    $.each(results.CatalogEntryView, function(index, item) {
        $.each(item.ItemDescription[0].features, function(k,v){
            $("#productHighlightsList").append("<li>" + k + v + "</li>");
        });
    });
});

So that we can test this, we must pretent we have your json:

var results = {
    'CatalogEntryView': [
        {
            'ItemDescription': [
                {
                    'features': {
                        '0': '<strong>A</strong>',
                        '1': '<strong>B</strong>',
                        '2': '<strong>C</strong>',
                        '3': '<strong>D</strong>',
                        '4': '<strong>E</strong>',
                        '5': '<strong>F</strong>',
                        '6': '<strong>G</strong>'
                    }
                }
            ]
        }
    ]
};

$.each(results.CatalogEntryView, function(index, item) {
    $.each(item.ItemDescription[0].features, function(k,v){
        $("#productHighlightsList").append("<li>" + k + v + "</li>");
    });
});

Working test on CodePen: https://codepen.io/skunkbad/pen/OjoBNb

Answer 2

Array.forEach function does not accumulate the array elements. You could use Array.reduce function to append all list items, and Array.map to wrap <li> tags around each of the items:

$.getJSON("item-data.json", function(results) {
    $.each(results.CatalogEntryView, function(index, item) {
        console.dir(item.ItemDescription[0].features);

        document.getElementById("productHighlightsList").innerHTML = item.ItemDescription[0].features.map(function(item){
            return "<li>" + item + "</li>";
        }).reduce(function(accumulator , item) {
            return accumulator + item;
        });
    });
});