How to return the current timestamp with Moment.js?

Question

Here you are assigning an instance of momentjs to CurrentDate:

var CurrentDate = moment();

Here just a string, the result from default formatting of a momentjs instance:

var CurrentDate = moment().format();

And here the number of seconds since january of… well, unix timestamp:

var CurrentDate = moment().unix();

And here another string as ISO 8601 (What’s the difference between ISO 8601 and RFC 3339 Date Formats?):

var CurrentDate = moment().toISOString();

And this can be done too:

var a = moment();
var b = moment(a.toISOString());

console.log(a.isSame(b)); // true