Adding 1 or 2 days to a date string

Question

I have got a string which is maybe date = "10/08/2011"; English time style.

Its a plain string, so I need to be able to add 1 or 2 days to it.

I have tried a few things but can't work it out as I am normally a PHP guy not JavaScript.

Any help is greatly appreciated.

Thanks

Lee

UPDATE

Why does this seem to be so hard, i've been stuck on this for an hour now..... I want to give the code a plain string which is mm/dd/yyyy - 10/08/2011 and i want back something like 11/08/2011

Why so hard ?? this is why i hate javascript and prefer PHP :-(

Answer 1

It's not all that complex:

//convert string to date
var dattmp = "10/08/2011".split('/').reverse().join('/');
var nwdate =  new Date(dattmp);

// to add 1 day use:
nwdate.setDate(nwdate.getDate()+1);

//to retrieve the new date use
[nwdate.getDate(),nwdate.getMonth()+1,nwdate.getFullYear()].join('/');

//all in one:
function dateAddDays( /*string dd/mm/yyyy*/ datstr, /*int*/ ndays){
  var dattmp = datstr.split('/').reverse().join('/');
  var nwdate =  new Date(dattmp);
  nwdate.setDate(nwdate.getDate() + (ndays || 1));
  return [ zeroPad(nwdate.getDate(), 10)
          ,zeroPad(nwdate.getMonth()+1, 10)
          ,nwdate.getFullYear() ].join('/');
}

//function to add zero to date/month < 10
function zeroPad(nr, base){
  var len = (String(base).length - String(nr).length) + 1;
  return len > 0? new Array(len).join('0') + nr : nr;
}

//examples
console.log(dateAddDays("10/08/2011"));     //=> 11/08/2011
console.log(dateAddDays("10/08/2011", -5)); //=> 05/08/2011

if you really want it simple - without using the Date Object:

console.log( '10/08/2011'
  .split('/')
  .map( (v, i) => i < 1 ? +v + 1 : v)
  .join('/') 
);

Here's a small function to convert a date(-time) string to a Date:

const log = Logger(document.querySelector(`pre`));
log(
  `<code>str2Date(\`3/15/2013T12:22\`, \`mdy\`)</code>\n  &gt; ${
    str2Date(`3/15/2013T12:22`, `mdy`)}`,
  `<code>str2Date(\`15-2013-03 12:22\`, \`dym\`)\</code>\n  &gt; ${
    str2Date(`15-2013-03 12:22`, `dym`)}`,
  `<code>str2Date(\`15/3/2013\`, \`dmy\`)</code>\n  &gt; ${
    str2Date(`15/3/2013`, `dmy`)}`,
  `<code>str2Date(\`2013/03/15\`)</code>\n  &gt; ${
    str2Date(`2013/03/15`)}` );

function str2Date(dateStr, ymd = `ymd`) {
  ymd = [...ymd].reduce( (acc, v, i) => ({...acc, [v]: i}), {} );
  const dt = dateStr.split(/[ T]/);
  const [d, t] = [ dt[0].split(/[/-]/), dt[1] ];
  return new Date( `${d[ymd.y]}-${d[ymd.m]}-${d[ymd.d]} ${t || ``}` );
}

function Logger(logEl) {
  return (...args) => {
    args.forEach(arg =>
      logEl.appendChild(
        Object.assign(document.createElement(`div`), {
          innerHTML: `${arg}`,
          className: `logEntry`
        })
      ))
  };
}

body {
  font: normal 12px/16px verdana, arial;
}

.logEntry {
  margin: 5px 0;
}

.logEntry:before {
  content: '• ';
  vertical-align: middle;
}

code {
  background-color: #eee;
  color: green;
  padding: 1px 2px;
}

<pre></pre>

Answer 2

To add 2 days:

var theDate = new Date("10/28/2011");
theDate.setDate(theDate.getDate()+2);

Answer 3

I tried this and got the result.

var dat = new Date('2018-03-16');

//use toISOString() to get the string value 2018-03-16T16:38:00.000Z
//substring(0,10) gets 2018-03-16
//reverse to gets 16-03-2018
var ret = dat.toISOString().substring(0, 10).split('-').reverse()

//rearranging to whatever format you want
var t = ret[0];
ret[0] = ret[1];
ret[1] = t;

//result
console.log(ret.join('/'))

Answer 4

You will need to convert the String into a Date-Object. With this you can call the .getDate() and setDate() - Functions to modify the date.

But to achieve this, the date has to be in one of the following formats:

1. MM/dd/yyyy
2. yyyy/MM/dd
3. MM-dd-yyyy
4. MMMM dd, yyyy
5. MMM dd, yyyy

So, maybe you would have to switch day and month in your string before converting, as I'm not sure if Month or Day is your first number.

For european Dates, you could change the string into the right format with something like this:

var date = "10/08/2011";
var eurDate = date.substr(3,2) + "/" + date.substr(0,2) + "/" + date.substr(6);

Links that could help you with this:

http://programming.top54u.com/post/Javascript-Convert-String-to-Date.aspx

http://www.adp-gmbh.ch/web/js/date/add_days.html

edit:

JSFiddle with an example: http://jsfiddle.net/4W8yM/11/

Answer 5

Try this

var date =  new Date("10/08/2011");

date = new Date(date.setDate(date.getDate()+1));//1 represents 1 day to add so you specify as per your need

var dateStr = date.getDay() + '/' + (date.getMonth() + 1) + '/' + date.getUTCFullYear();

Answer 6

You must enforce a string to be interpreted as date-month-year or or month-date-year, or it will depend on the user's settings.

You can assemble the date from the string to ensure the date-month format:

Date.fromDM=function(string){
    var A= string.match(/([1-9]\d*)/g);
    if(A.length!== 3) throw 'bad date'; 
    return new Date(A[2]*1, A[1]-1, A[0]*1);
}
Date.fromMD=function(string){
    var A= string.match(/([1-9]\d*)/g);
    if(A.length!== 3) throw 'bad date'; 
    return new Date(A[2]*1, A[0]-1, A[1]*1);
}



/*  Date.fromDM('10,08,2011')
return value: (Date)
Wed Aug 10 2011 00:00:00 GMT-0400 (Eastern Daylight Time)
*/

/*Date.fromMD('10,08,2011')
return value: (Date)
Sat Oct 08 2011 00:00:00 GMT-0400 (Eastern Daylight Time)
*/