Parse result as JSON on $.ajax error

parseError.js

$.ajaxPrefilter(function (options, originalOptions, jqXHR) {
    if (options.parseError) {
        $.Deferred(function (defer) {
            jqXHR.done(defer.resolve)
                .fail(function (jqXHR, statusText, errorMsg) {
                    var parsed = $.parseJSON(jqXHR.responseText);
                    defer.rejectWith(this, [jqXHR, statusText, parsed]);
                });
        }).promise(jqXHR);
        jqXHR.success = jqXHR.done;
        jqXHR.error = jqXHR.fail;
    }
});

$.ajax({
    type: "POST",
    url: form.attr("action"),
    data: form.serialize(),
    dataType: "json",
    parseError: true,
    success: function (data) { window.location.href = data.url; },
    error: function (jqXHR, textStatus, errorMsg) {
        console.log(errorMsg); //now json
    }

});