Options.js

//@ts-check

class Options {
    /**
     * A helper method to extend the default options with user supplied ones.
     */
    static extend() {
        let that = this;
        let extended = {};
        let deep = false;
        let i = 0;
        let length = arguments.length;

        if (Object.prototype.toString.call(arguments[0]) === '[object Boolean]') {
            deep = arguments[0];
            i++;
        }

        let merge = function (obj) {
            for (var prop in obj) {
                if (Object.prototype.hasOwnProperty.call(obj, prop)) {
                    if (deep && Object.prototype.toString.call(obj[prop]) === '[object Object]') {
                        extended[prop] = that.extend(true, extended[prop], obj[prop]);
                    } else {
                        extended[prop] = obj[prop];
                    }
                }
            }
        };

        for (; i < length; i++) {
            let obj = arguments[i];
            merge(obj);
        }

        return extended;
    }
}

module.exports = Options;