Simple console logger with custom css styles and tree-style displaying objects

Logger.js

(function () {

    this.Logger = function(){
        var defaults = {
            style : 'background: white; color: black; display: block;',
            tag: 'DEFAULT'
        };

        if (arguments[0] && typeof arguments[0] === "object") {
            this.options = _extendDefaults(defaults, arguments[0]);
        }
        this.message_template = `%c${_time()} [${this.options.tag}]:`;
    };


    Logger.prototype = {
        debug : function(message){
            console.debug(`${this.message_template} ${message}`, this.options.style);
        },
        error : function(message){
            console.error(`${this.message_template} ${message}`, this.options.style);
        },
        log : function(message){
            console.log(`${this.message_template} ${message}`, this.options.style);
        },
        warn : function(message){
            console.warn(`${this.message_template} ${message}`, this.options.style);
        },
        object : function (name, obj){
            console.log(`${this.message_template}`, this.options.style);
            console.groupCollapsed(`%cObject \'${name}\'`,this.options.style);
            _outputObject("",obj,this.options.style);
            console.groupEnd();
        },
    };

    var _outputObject = function(name,obj,style) {
        var property;
        for (property in obj) {
            if (!_isObject(obj[property]))
                console.log(`%c${property}: ${obj[property]}`,style);
            else {
                console.groupCollapsed(`%c${property}`,style);
                _outputObject(property,obj[property],style);
            }
        }
        if (name != "" || name != undefined)
            console.groupEnd();
    };

    var _isObject = function (val) {
        if (val === null) { return false;}
        // without arrays
        return ( (typeof val === 'function') || (typeof val === 'object') && !(Array.isArray(val)) );
    };

    var _extendDefaults = function (source, properties) {
        var property;
        for (property in properties) {
            if (properties.hasOwnProperty(property)) {
                source[property] = properties[property];
            }
        }
        return source;
    };

    var _time = function () {
        return (`[${new Date().toISOString()}]`);
    };

}());
/*
Example of usage

var logger = new Logger( { style : 'background: green; color: white; display: block;'});

logger.debug("test");

// display options object
logger.object("Options", logger.options);
*/