javascript - How can I convert a date into an integer? -

i have array of dates , have been using map function iterate through it, can't figure out javascript code converting them integers.

this array of dates:

var dates_as_int = [     "2016-07-19t20:23:01.804z",     "2016-07-20t15:43:54.776z",     "2016-07-22t14:53:38.634z",     "2016-07-25t14:39:34.527z" ]; 

var dates = dates_as_int.map(function(datestr) {     return new date(datestr).gettime(); }); 

=>

[1468959781804, 1469029434776, 1469199218634, 1469457574527] 

---

update: es6 version:

const dates = dates_as_int.map(date => new date(date).gettime())