how to get Previous Day?

I have date object:

dateObj = new Date(year, month, date[, hours, minutes, seconds, ms] )

How to get dateObj - 1 da开发者_StackOverflow社区y ?

dateObj.setDate(dateObj.getDate()-1);

By subtracting one day (1000 ms * 60 sec * 60 min * 24 hours):

new Date(+new Date(year, month, date[, hours, minutes, seconds, ms] ) - 1000*60*60*24);

Some useful functions that doesnt mutate the orignal date object:

function prevDate(date) {
  let copy = new Date(date.valueOf());
  return new Date(copy.setDate(copy.getDate() - 1));
}

function nextDate(date) {
  let copy = new Date(date.valueOf());
  return new Date(copy.setDate(copy.getDate() + 1));
}

Have a look at the moment.js library https://momentjs.com/docs/

To get the date previous day you would simply need to do...

moment().add(-1, 'days');