Các vấn đề khi làm việc với ngày tháng trong javascript

// ngày giờ hiện tại
new Date();

// nếu truyền vào 0, chúng ta có giá trị Jan 1st 1970 (UTC)
new Date(0);

const timestamp = 1530826365;
new Date(timestamp * 1000);

new Date("2018-07-22");
new Date("2018-07"); //July 1st 2018, 00:00:00
new Date("2018"); //Jan 1st 2018, 00:00:00
new Date("07/22/2018");
new Date("2018/07/22");
new Date("2018/7/22");
new Date("July 22, 2018");
new Date("July 22, 2018 07:22:13");
new Date("2018-07-22 07:22:13");
new Date("2018-07-22T07:22:13");
new Date("25 March 2018");
new Date("25 Mar 2018");
new Date("25 March, 2018");
new Date("March 25, 2018");
new Date("March 25 2018");
new Date("March 2018"); //Mar 1st 2018, 00:00:00
new Date("2018 March"); //Mar 1st 2018, 00:00:00
new Date("2018 MARCH"); //Mar 1st 2018, 00:00:00
new Date("2018 march"); //Mar 1st 2018, 00:00:00

`YYYY-MM-DDTHH:mm:ss:sssZ`;

Date.parse("2018-07-22");
Date.parse("2018-07"); //July 1st 2018, 00:00:00
Date.parse("2018"); //Jan 1st 2018, 00:00:00
Date.parse("07/22/2018");
Date.parse("2018/07/22");
Date.parse("2018/7/22");
Date.parse("July 22, 2018");
Date.parse("July 22, 2018 07:22:13");
Date.parse("2018-07-22 07:22:13");
Date.parse("2018-07-22T07:22:13");

new Date(2018, 6, 22, 7, 22, 13, 0);
new Date(2018, 6, 22);

// bằng cách thêm +HOURS
new Date("July 22, 2018 07:22:13 +0700");

// bằng cách thêm tên , ICT gồm Campuchia, Lào, Thái Lan, Việt Nam
new Date("July 22, 2018 07:22:13 (ICT)");

const date = new Date("July 22, 2018 07:22:13");

date.toString();
// "Sun Jul 22 2018 07:22:13 GMT+0200 (Central European Summer Time)"
date.toTimeString();
//"07:22:13 GMT+0200 (Central European Summer Time)"
date.toUTCString();
//"Sun, 22 Jul 2018 05:22:13 GMT"
date.toDateString();
//"Sun Jul 22 2018"
date.toISOString();
//"2018-07-22T05:22:13.000Z" (ISO 8601 format)
date.toLocaleString();
//"22/07/2018, 07:22:13"
date.toLocaleTimeString();
//"07:22:13"
date.getTime();
//1532236933000
date.getTime();
//1532236933000

const date = new Date("July 22, 2018 07:22:13");

date.getDate(); //22
date.getDay();
//0 (0 là chủ nhật, 1 là thứ 2..)
date.getFullYear(); //2018
date.getMonth(); //6 (Bắt đầu từ 0)
date.getHours(); //7
date.getMinutes(); //22
date.getSeconds(); //13
date.getMilliseconds(); //0 (không xác định)
date.getTime(); //1532236933000
date.getTimezoneOffset();
//-120 (Tùy theo khu vực và vùng miền).

date.getUTCDate(); //22
date.getUTCDay(); //0 (0 means sunday, 1 means monday..)
date.getUTCFullYear(); //2018
date.getUTCMonth(); //6 (starts from 0)
date.getUTCHours(); //5 (not 7 like above)
date.getUTCMinutes(); //22
date.getUTCSeconds(); //13
date.getUTCMilliseconds(); //0 (not specified)

const date = new Date("July 22, 2018 07:22:13");

date.setDate(newValue);
date.setDay(newValue);
date.setFullYear(newValue); //note: đừng dùng setYear(), bỏ rồi
date.setMonth(newValue);
date.setHours(newValue);
date.setMinutes(newValue);
date.setSeconds(newValue);
date.setMilliseconds(newValue);
date.setTime(newValue);
date.setTimezoneOffset(newValue);

const date = new Date("July 22, 2018 07:22:13");

date.setUTCDate(newalue);
date.setUTCDay(newValue);
date.setUTCFullYear(newValue);
date.setUTCMonth(newValue);
date.setUTCHours(newValue);
date.setUTCMinutes(newValue);
date.setUTCSeconds(newValue);
date.setUTCMilliseconds(newValue);

Date.now();
// tương tự như viết
new Date().getTime();

new Date(2018, 6, 40);
//Thu Aug 09 2018 00:00:00 GMT+0200

// "12/22/2017"
const date = new Date("July 22, 2018 07:22:13");
new Intl.DateTimeFormat().format(date);

// định dạng kiểu Mỹ
new Intl.DateTimeFormat("en-US").format(date); //"7/22/2018"

// đưa thêm option để customize lại output
const options = {
  year: "numeric",
  month: "numeric",
  day: "numeric",
  hour: "numeric",
  minute: "numeric",
  second: "numeric"
};

new Intl.DateTimeFormat("en-US", options).format(date); //"7/22/2018, 7:22:13 AM"
new Intl.DateTimeFormat("it-IT", options2).format(date); //"22/7/2018, 07:22:13"

const date1 = new Date("July 10, 2018 07:22:13");
const date2 = new Date("July 22, 2018 07:22:13");
const diff = date2.getTime() - date1.getTime();

const date1 = new Date("July 10, 2018 07:22:13");
const date2 = new Date("July 10, 2018 07:22:13");
if (date2.getTime() === date1.getTime()) {
  //dates are equal
}