How to annotate a nested object in javascript for the Closure Compiler and have all the properties optional?

Question

Here is my class A, and I want all options to be optional. It works fine for properties a, b, c, but does not work for c.cX properties. How to do it right to make all properties optional?

// ==ClosureCompiler==
// @compilation_level ADVANCED_OPTIMIZATIONS
// @output_file_name default.js
// ==/ClosureCompiler==

/**
 * @typedef {{
 *     a: (string|undefined),
 *     b: (number|undefined),
 *     c: ({
 *         ca: (string|undefined),
 *         cb: (number|undefined),
 *         cc: (Function|undefined)
 *     }|undefined)
 * }}
 */
var Options;


/**
 * @param {Options=} options
 * @constructor
 */
var A = function(options) {
    console.log(this);
};


new A({
    a: 'x',
    c: {
        ca: 'x',
        //cb: 1,
        cc: function() {}
    }
});

Answer 1

Options type must be defined as follows:

/**
 * @record
 * @struct
 */
function Options() {};

/** @type {string|undefined} */
Options.prototype.a;

/** @type {number|undefined} */
Options.prototype.b;

/** @type {!OptionsC|undefined} */
Options.prototype.c;


/**
 * @record
 * @struct
 */
function OptionsC() {};

/** @type {string|undefined} */
OptionsC.prototype.ca;

/** @type {number|undefined} */
OptionsC.prototype.cb;

/** @type {Function|undefined} */
OptionsC.prototype.cc;