See some of the useful single line JavaScript snippets for dealing with dates
Cheking
Is Before
Check if a date is before another date.
// 2020/10/20 is before 2020/10/21
new Date('2020/10/20') < new Date('2020/10/21');
// => true
Is Same
Check if a date is the same as another date.
// '2020-10-20' is same of '2020-10-21'
new Date(2020, 9, 20).valueOf() === new Date(2020, 9, 21).valueOf();
// => false
new Date(2020, 9, 20).valueOf() === new Date(2020, 9, 20).valueOf();
// => true
new Date(2020, 9, 20).getTime() === new Date(2020, 9, 20).getTime();
// => true
new Date(2020, 9, 20).valueOf() === new Date(2020, 9, 20).getTime();
// => true
new Date(2020, 9, 20).toDateString().substring(4, 7) ===
new Date(2020, 9, 21).toDateString().substring(4, 7);
// => true
Is After
Check if a date is after another date
new Date(2020, 9, 20) > new Date(2020, 9, 19);
// => true
Is Leap Year
Check if a year is a leap year
new Date(2000, 1, 29).getDate() === 29;
// => true
Is a Date
Check if a variable is a native js Date object.
new Date() instanceof Date;
// => true
Get Or Set
Get the Millisecond/Second/Minute/Hour of the given date
new Date().getSeconds();
// => 49
new Date().getHours();
// => 19
Set the Millisecond/Second/Minute/Hour of the given date.
new Date(new Date().setSeconds(30));
// => "2020-09-09T09:12:30.695Z"
new Date(new Date().setHours(13));
// => "2020-09-09T03:12:49.695Z"
Date of Month
Gets the day of the month.
new Date().getDate();
// => 9
Sets the day of the month
new Date().setDate(4);
// => "2020-09-04T09:12:49.695Z"
Day of Week
Gets the day of the week.
new Date().getDay();
// => 0 (Sunday)
Sets the day of the week
new Date().setDate(new Date().getDate() - 14);
// => "2020-08-26T09:12:49.695Z"
Day of Year
Gets or sets the day of the year.
Math.floor(
(new Date() - new Date(new Date().getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24
);
// => 252
Week of Year
Gets the week of the year
const day = new Date();
const MILLISECONDS_IN_WEEK = 604800000;
const firstDayOfWeek = 1; // monday as the first day (0 = sunday)
const startOfYear = new Date(day.getFullYear(), 0, 1);
startOfYear.setDate(
startOfYear.getDate() + (firstDayOfWeek - (startOfYear.getDay() % 7))
);
const dayWeek = Math.round((day - startOfYear) / MILLISECONDS_IN_WEEK) + 1;
// => 37
Sets the week of the year
const day = new Date();
const week = 24;
const MILLISECONDS_IN_WEEK = 604800000;
const firstDayOfWeek = 1; // monday as the first day (0 = sunday)
const startOfYear = new Date(day.getFullYear(), 0, 1);
startOfYear.setDate(
startOfYear.getDate() + (firstDayOfWeek - (startOfYear.getDay() % 7))
);
const dayWeek = Math.round((day - startOfYear) / MILLISECONDS_IN_WEEK) + 1;
day.setDate(day.getDate() - (dayWeek - week) * 7);
day.toISOString();
// => "2020-06-10T09:12:49.794Z
Days in Month
Get the number of days in the current month
new Date(2012, 02, 0).getDate();
// => 29
Parse
Return the Date parsed from date string using the given format string
const datePattern = /^(\d{2})-(\d{2})-(\d{4})$/;
const [, month, day, year] = datePattern.exec('12-25-1995');
new Date(`${month}, ${day} ${year}`);
// => "1995-12-24T13:00:00.000Z"
Return the Date parsed from time string using the given format string
const datePattern = /^(\d{4})-(\d{2})-(\d{2})\s(\d{1,2}):(\d{2})$/;
const [, year, month, day, rawHour, min] = datePattern.exec('2010-10-20 4:30');
new Date(`${year}-${month}-${day}T${('0' + rawHour).slice(-2)}:${min}:00`);
// => "2010-10-19T17:30:00.000Z"
Manipulate
Add
Add the specified number of days to the given date.
// add 7 days
const now = new Date();
now.setDate(now.getDate() + 7);
// => "Sun Sep 16 2018 09:12:49"
Subtract
Subtract the specified number of days from the given date.
// subsctact 7 days
new Date(new Date().getTime() - 1000 * 60 * 60 * 24 * 7);
// => Sun Sep 09 2018 09:12:49
End of Time
Return the end of a unit of time for the given date.
const end = new Date();
end.setHours(23, 59, 59, 999);
end.toISOString();
// => "2018-09-09T16:59:59.999Z"
Display
Time from now
Return time from now.
new Intl.RelativeTimeFormat().format(-4, 'day');
// => "4 days ago"
Difference
Get the unit of time between the given dates
// difference betwwen '2007-01-27' to '2007-01-29'
new Date(2007, 0, 27) - new Date(2007, 0, 29);
// => -172800000
Math.ceil(
(new Date(2007, 0, 27) - new Date(2007, 0, 29)) / 1000 / 60 / 60 / 24
);
// => -2
Top comments (3)
How do you make your animation
I use google slides
thank you