Dev tools snippet

gistfile1.txt

var watchMe = {};

Object.observe(watchMe, function(options) {
    options.forEach(function(option) {
        var groupName = option.name + ' changed';
        console.groupCollapsed(groupName);
        console.log('Old value: ', option.oldValue);
        console.log('New value: ', option.object[option.name]);
        console.groupEnd(groupName);    
    });
});