XML to JSON and JSON to XML Conversion in Javascript

When we deal with today's highly ajax based web application developments, dealing with XMLs within your page might be a little bit tedious task. As all of us know, JavaScript doesn't have a proper way to deal with XMLs(although recent specs supports E4X, it hasn't implemented in all browsers). If we can convert the XML into a JSON format, then it will be a great relief for web developers.

Although there are many XML to JSON notations available, all of them tends to ignore xml namespaces, but Badgerfish. So, I thought of writing a JavaScript code which does the XML to JSON conversion and wise-versa. If you want to get the Javascript code for XML to JSON, then go though my blog post XML to BadgerFish Conversion in Javascript. In this post, I will give you the function which converts JSON back to it's original XML.

Using these xml2bf and bf2xml functions, you will get the most flexibility with XML in your web developments.

function bf2xml(json) {
    if (typeof json !== "object") return null;
    var cloneNS = function(ns) {
        var nns = {};
        for (var n in ns) {
            if (ns.hasOwnProperty(n)) {
                nns[n] = ns[n];
            }
        }
        return nns;
    };
    var processLeaf = function(lname, child, ns) {
        var body = "";
        if (child instanceof Array) {
            for (var i = 0; i < child.length; i++) {
                body += processLeaf(lname, child[i], cloneNS(ns));
            }
            return body;
        } else if (typeof child === "object") {
            var el = "<" + lname;
            var attributes = "";
            var text = "";
            if (child["@xmlns"]) {
                var xmlns = child["@xmlns"];
                for (var prefix in xmlns) {
                    if (xmlns.hasOwnProperty(prefix)) {
                        if (prefix === "$") {
                            if (ns[prefix] !== xmlns[prefix]) {
                                attributes += " " + "xmlns=\"" + xmlns[prefix] + "\"";
                                ns[prefix] = xmlns[prefix];
                            }
                        } else if (!ns[prefix] || (ns[prefix] !== xmlns[prefix])) {
                            attributes += " xmlns:" + prefix + "=\"" + xmlns[prefix] + "\"";
                            ns[prefix] = xmlns[prefix];
                        }
                    }
                }
            }
            for (var key in child) {
                if (child.hasOwnProperty(key) && key !== "@xmlns") {
                    var obj = child[key];
                    if (key === "$") {
                        text += obj;
                    } else if (key.indexOf("@") === 0) {
                        attributes += " " + key.substring(1) + "=\"" + obj + "\"";
                    } else {
                        body += processLeaf(key, obj, cloneNS(ns));
                    }
                }
            }
            body = text + body;
            return (body !== "") ? el + attributes + ">" + body + "</" + lname + ">" : el + attributes + "/>"
        }
    };
    for (var lname in json) {
        if (json.hasOwnProperty(lname) && lname.indexOf("@") == -1) {
            return processLeaf(lname, json[lname], {});
        }
    }
    return null;
}