createContentType.js

createcontenttype: function () {
    var dfd = $.Deferred();

    var ctx = getContext();
    var appctx = getAppContextSite(ctx);

    var targetWeb = appctx.get_site().get_rootWeb();
    var fields = targetWeb.get_fields()
    var field = fields.getByInternalNameOrTitle(sitecolumnname);
    ctx.load(fields);
    ctx.load(field);
    var ctci = constructContentTypeCreationInformation(contenttypeid, contenttypename)
    var newType = targetWeb.get_contentTypes().add(ctci);
    ctx.load(newType);

    ctx.executeQueryAsync(succeed, fail);
    function succeed(sender, args) {
        var fieldRefs = newType.get_fieldLinks();
        ctx.load(fieldRefs);
        ctx.executeQueryAsync(
            function () {
                var flci = constructFLCI(field);
                newType.get_fieldLinks().add(flci);
                newType.update();
                ctx.executeQueryAsync(function () { dfd.resolve(); },
                    function (sender, args) {
                        console.log("Content type creation failure: " + args.get_message());
                        dfd.reject();
                    });
            },
            function (sender, args) {
                console.log("Content type creation failure: " + args.get_message());
                dfd.reject();
            });
    }
    function fail(sender, args) {
        console.log("Content type creation failure: " + args.get_message());
        dfd.reject();
    }
    return dfd.promise();
}