A centralized way to modify jquery ajax responses. Usefull in testing where you need semi-mocks

alter-ajax-response.js

    var alterResponse = function (opts) {
        /**
         * Function modifies $.ajax responses
         * by allowing you to modify ajax response object before each bound success callback.
         * Currently it supports only `success` callbacks, `error` and `complete` support to come.
         * @param {RegExp} opts.urlMatch - use this to filter calls by url
         * @param {String} opts.dataType - Optional - use this to filter calls by response type
         * @param {Function} opts.successWrapper - function that gets called before each ajax callback
         *          - function (options:Object, originalOptions:Object, jqXHR:jQuery.XHR, originalSuccess: Function)
         */
        var callback = function (options, originalOptions, jqXHR) {
            var check = true;
            if (opts.urlMatch && !options.url.match(opts.urlMatch)) check = false;
            if (opts.typeMatch && !options.type.match(opts.typeMatch)) check = false;
            if (check) {
                var originalSuccess = originalOptions.success || options.success;
                var next = function (data) {
                    originalSuccess(data);
                };
                originalOptions.success = options.success = function () {
                    // In your wrapper, call next() after you changed the response.
                    opts.successWrapper.call(null, options, originalOptions, jqXHR, next);
                };
            }
        };
        if (opts.dataTypes) {
            $.ajaxPrefilter(opts.dataTypes, callback);
        }
        else {
            $.ajaxPrefilter(callback);
        }
    };

usage-example.js

alterResponse({
        urlMatch: /user/g,
        typeMatch: /get/gi,
        successWrapper: function (options, originalOptions, jqXHR, next) {
            var response = JSON.parse(jqXHR.responseText);
            response.name = 'Some other name'
            next(response);
        }
});

This is great, but it doesn't work if someone is using the .done() promise as a handler.