I am reading a date from local storage and then need to compare it to another date but it does not work. I think I need to typecast it but am very rusty with Javascript, please have a look, my code is not much:
// ****** ### IMPORTANT: The below line returns "2011,3,20" ### *******
var da_expiry_date = localStorage['list_expiry_date'];
var today_date = new Date();
var future_date = new Date();
future_date.setFullYear(da_expiry_date+2);
alert (future_date+"\n"+today_date);
if (future_date>today_date) {
alert("1");
}
else {
alert("2");
}
Thanks in advance!
If you're comment at the top is correct and da_expiry_date is returning a string, then you will need to typecast it to date before you can do anything meaningful. The easiest way to do this is with oneof the methods listed here. The problem with converting a string to a date is knowing the format; if you have all the pieces separated you can just use one of the other date constructors. :D
As it is, you code is trying to take the string "2011,3,20", add the number 2 to it, and set it as the full year of future_date. The browser ends up converting 2 to a string and concatenating that to the end, giving you "2011,3,202". setFullYear expects an int instead of a string, so it can't do its job.
You probably want that line switched to this after you've got your date properly converted:
future_date.setFullYear(da_expiry_date.getFullYear()+2);
I'm not sure what you're attempting with this line:
da_expiry_date+2;
The result of that is:
2011,3,202
...which is not a valid value to pass to setFullYear. So, let's parse the date:
var da_expiry_date = localStorage['list_expiry_date'];
function pad(num, n) {
return ("0" + num).slice(-n);
}
function formatDate(date) {
var p = date.split(",");
return [pad(p[0], 4), pad(p[1], 2), pad(p[2], 2)].join("-");
}
var today_date = new Date();
var future_date = new Date(formatDate(da_expiry_date));
alert (future_date+"\n"+today_date);
if (future_date>today_date) {
alert("1");
} else {
alert("2");
}
If you're attempting to add 2 to the year, then do it after you've split the date into its components:
function formatDate(date) {
var p = date.split(",");
p[0] = p[0] * 1 + 2; // add 2 to the year
return [pad(p[0], 4), pad(p[1], 2), pad(p[2], 2)].join("-");
}
Or, even better, parameterize it:
function formatDate(date, n) {
var p = date.split(",");
p[0] = p[0] * 1 + n; // add n to the year
return [pad(p[0], 4), pad(p[1], 2), pad(p[2], 2)].join("-");
}
You'll need to parse it as a date first, try this:
var dateFromLocalStorage = function(s) {
var m = (""+s).match(/^(\d+),(\d+),(\d+)$/);
return (m) ? new Date(m[1], m[2], m[3]) : null;
};
dateFromLocalStorage("2011,3,20"); // => Wed Apr 20, 2011 ...
Note that the date constructor takes the month as a zero based integer, so Jan=0, Feb=1, Mar=2, etc.
Related
I have a bunch of timestamps that have the following format: Year:Month:Day:Hour:Minute:Second, for example, 2017:01:01:23:59:59. All domains are zero-padded decimal numbers.
I am trying to write a function to determine if a given timestamp is within a range:
function isBetween(start, end, toCompare) {
}
for example, isBetween('2017:01:01:23:59:58', "2017:01:02:23:59:58", "2017:01:01:23:59:59") should return true as "2017:01:01:23:59:59" is between '2017:01:01:23:59:58' and "2017:01:02:23:59:58"
I couldn't find a clean way to do it. Can someone help me with this?
In JavaScript, Date objects can be compared fairly easily. However, as you've probably noticed, the format of the string you provided is not a format that can be parsed by JavaScript's Date object, so we will first have to fix that. Fortunately, this format is extremely predictable.
The first thing I notice is that the "Month" and "Date" are preceded by a zero if they're a single digit. This means that the date portion is always the exact same amount of characters (10). Because this is the case, we can use String.prototype.substring() to get the first 10 characters for the date, and get everything after the 11th character to get the time while skipping the colon in the middle.
var datetime = "2017:01:01:23:59:58";
var date = datetime.substring(0, 10);
var time = datetime.substring(11);
console.log("Date: " + date);
console.log("Time: " + time);
Now that they're separate, all we need to do is replace the colons in the date with forward slashes, then concatenate it with the time separated by a space. After this, we will have a date string in the MM/dd/yyyy hh:mm:ss format, which we can then parse using JavaScript's built in Date class.
var input = "2017:01:01:23:59:58";
var date = input.substring(0, 10).replace(/:/g, "/");
var time = input.substring(11);
var datetime = date + " " + time;
console.log(new Date(datetime));
Now we can throw this into it's own function, then use simple comparison to figure out if toCompare is between start and end.
function isBetween(start, end, toCompare) {
var startDate = convertDate(start);
var endDate = convertDate(end);
var compareDate = convertDate(toCompare);
return compareDate > startDate &&
compareDate < endDate
}
function convertDate(input){
var date = input.substring(0, 10).replace(/:/g, "/");
var time = input.substring(11);
var datetime = date + " " + time;
return new Date(datetime);
}
var between = isBetween("2017:01:01:23:59:58", "2017:01:02:23:59:58", "2017:01:01:23:59:59");
console.log(between)
This could work for you:
function isBetween(start, end, toCompare) {
start = dateGenerator(start)
end = dateGenerator(end)
toCompare = dateGenerator(toCompare)
if(start <= toCompare && toCompare <= end) return true
return false
}
function dateGenerator(str) {
str = str.split(":")
let date = new Date(`${str[0]}-${str[1]}-${str[2]}`)
date.setHours(str[3],str[4],str[5])
return date.valueOf()
}
const truthy = isBetween('2017:01:01:23:59:58', "2017:01:02:23:59:58", "2017:01:01:23:59:59")
console.log(truthy)
Firstly get individual values and add accordingly to Date constructor of JS and set the hours accordingly.
For comparison we can convert this unix figures (valueOf), hence it will be easier to compare.
This may seem as complex approach but it works.
I have an array with many dates, they are not in the date type but string like: "2016-08-12" for example. Then what I would like to do is to remove all dates that we already have passed. So therefor im trying to compare them to todays date and then remove it if its passed. Using typescript by the way.
my array, named datoArray, looks like this:
["2016-08-02", "2016-08-11", "2016-08-22", "2016-09-10"]
just with a lot more of the same...
then here's what I try to do:
for(var i = 0; i < this.datoArray.length; i++){
this.skoleAar = parseInt(this.datoArray[i].slice(0,4))
this.skoleMaaned = parseInt(this.datoArray[i].slice(5,8))
this.skoleDag = parseInt(this.datoArray[i].slice(8,10))
if(this.skoleAar < dagensAar){
this.datoArray.splice(i, 1);
}
if(this.skoleAar == dagensAar && this.skoleMaaned < dagensMaaned){
this.datoArray.splice(i, 1);
}
if(this.skoleAar == dagensAar && this.skoleMaaned == dagensMaaned && this.skoleDag < dagensDag){
this.datoArray.splice(i, 1);
}
}
the "dagensAar", "dagensMaaned" and "dagensDag" variables im getting from another function that works. If i "console.log" the variables it prints out int values like 2016 for the year and 8 for the month if i take from the start of the array, and for the "dagensAar", "dagensMaaned" and "dagensDag" it prints 2016 11 20, which is todays year, month and day. all is in Int type, so what im not getting here is why my "if" doesnt work? It seems like there is something wrong with the way i compare the, but i thought this was the way to compare int values?
If the dates are in ISO-8601 format then you can simply filter using Date.parse().
var dates = ["2016-08-02", "2016-08-11", "2016-08-22", "2016-09-10", "2016-12-15"];
function removePastDates(data) {
var today = new Date();
console.log('Initial state: ' + data);
var modified = dates.filter(function(dateString) {
return Date.parse(dateString) >= today;
});
console.log('Final state: ' + modified);
return modified;
}
var newDates = removePastDates(dates);
Your dates seem to be RFC compliant, meaning they can be directly fed into a new Date object. Simply compare to today and filter by that:
var today = new Date()
var futureDates = this.datoArray.filter(d => new Date(d) >= today)
(pre-ECMA6:)
var today = new Date()
var futureDates = this.datoArray.filter(function (d) {
return new Date(d) >= today;
})
I think the problem is not related to the dates.
I think the problem is that you are removing items from the array while looping the same exact array.
You should maybe try looping from the end of the array to the beginning or just save the indexes that you need to remove and later do the actual removing.
Keep in mind that when you remove an item you change the index of every item in the remaining of the array - maybe you should start removing from the greatest index so it will not confuse you.
I want to validate dates by Javascript and found this nice answer:
https://stackoverflow.com/a/1353711/3391783
but when i try to use it to validate dates, it seems like Javascript is auto-correcting my date by taking the closest valid date. so this will return true even though 2014-11-31 is not a valid date (Javascript months start at 0, so 10 equals November):
function isValidDate(d) {
if ( Object.prototype.toString.call(d) !== "[object Date]" )
return false;
return !isNaN(d.getTime());
}
var test_date = new Date(2014, 10, 31);
console.log( test_date );
console.log( isValidDate(test_date) );
seems like creating the Date is automatically switching it to 2014-12-01 which is a correct date.
but I would like to be able to validate user input without changing it.
So how can i create an invalid new Date() in Javascript?
Or is there a much simpler way to do this?
You can use the auto-correction in the Date object to validate the date. Just check the input against what you have in the Date object:
var y = 2014, m = 10, d = 31;
var test_date = new Date(y, m, d);
var valid =
test_date.getFullYear() == y &&
test_date.getMonth() == m &&
test_date.getDate() == d;
document.write(valid);
When it comes to handling dates in JavaScript, I'm a big fan of Moment.js. As you can see here, they do a good job of validating dates: http://momentjs.com/docs/#/parsing/is-valid/
new Date(2013, 25, 14).toString(); // "Sat Feb 14 2015 00:00:00 GMT-0500 (EST)"
moment([2015, 25, 35]).format(); // 'Invalid date'
Here's a function I wrote a while back that demonstrates Guffa's solution.
function isValidDate(checkDate) {
if(!/\d\d\/\d\d\/\d\d\d\d/.test(checkDate)) {
return false; // checkDate is not formatted as ##/##/####
} else {
// split checkDate into three pieces
var strMM = checkDate.split('/')[0];
var strDD = checkDate.split('/')[1];
var strYYYY = checkDate.split('/')[2];
// create new Date() object from split pieces
var strDateCheck = new Date(strYYYY,(strMM - 1),strDD);
// evaluate each piece of resulting date object against each corresponding piece of checkDate
if(((strDateCheck.getMonth() + 1) == strMM) && (strDateCheck.getDate() == strDD) && (strDateCheck.getFullYear() == strYYYY)) {
/* if you wish, add additional validation constraints here */
return true; // all three pieces match exactly
} else {
return false; // at least one piece did not match
}
}
}
I am trying this to validate the date.However I am not too sure about what is wrong with this.
Note- I my application there is no space between mm(minuted) and AM/PM.
var date = '21/01/13 6:40AM';
var myRegex = /0?[0-31]\d\/0?[0-12]\d\/\d{2} [0-11]\d:[0-59]\d[AP][M]/;
if (myRegex.test(date)){
// Ok to proceed
}
I tried the following by breaking the date and time separately i.e the following combination
var date = '21/01/13'
var myRegex = /0?[0-31]\d\/0?[0-12]\d\/d{2}/;
However for the time part i.e 6:40AM.I am not able to validate it with
var myRegex = /[0-11]\d:[0-59]\d[AP][M]/;
Could you please help me out.
Try This One. Leap year supported. example: http://jsfiddle.net/Vk268/
^(((0[1-9]|[12]\d|3[01])\/(0[13578]|1[02])\/((19|[2-9]\d)\d{2}))|((0[1-9]|[12]\d|30)\/(0[13456789]|1[012])\/((19|[2-9]\d)\d{2}))|((0[1-9]|1\d|2[0-8])\/02\/((19|[2-9]\d)\d{2}))|(29\/02\/((1[6-9]|[2-9]\d)(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00))))$
Try This :
var regex = /^([0-11]\d):([0-59]\d)\s?(?:AM|PM)?$/i;
Will work for : "06:40am"
I suggest you to check actual validity not just syntax. check this post which uses datejs
Jquery DateJs, is there validation for full date?
One way to validate date and time strings is to create a date object and see if the parts match, e.g.
function validateDateString(s) {
var b = s.split(/[\/ :]/g);
var ap = s.substring(-2).toLowerCase();
var h = parseInt(b[3], 10) + (ap == 'am'? 0 : 12);
var min = parseInt(b[4],0);
var y = +b[2] + (b[2] < 50? 2000 : 1900);
var d = new Date(y, --b[1], b[0], h, min, 0, 0);
var apValid = /am|pm/.test(ap);
// Only need to test two parts of date and hours
return d.getMonth() == b[1] && d.getDate() == b[0] && d.getHours() == h && apValid;
}
console.log(validateDateString('21/01/13 6:40AM')); // true
You could use a regular expression too, and if ES5 compliant browsers are all you need to support you could reformat the string as an ISO 8601 compliant string a pass it to Date.parse. But that won't work in many browsers in use.
I need to validate different date's with some javascript(jquery).
I have a textbox with, the inputmask from jquery (http://plugins.jquery.com/plugin-tags/inputmask). The mask that i use is "d/m/y".
Now i have set up a CustomValidator function to validate the date.
I need 2 functions. One to check if the given date is greater then 18 years ago. You must be older then 18 year.
One function to check if the date is not in the future. It can only in the past.
The function are like
function OlderThen18(source, args) {
}
function DateInThePast(source, args) {
}
As you know the value you get back with args.Value is 27/12/1987 .
But how can i check this date in the functions? So that i can set args.IsValid to True or False.
I tried to parse the string(27/12/1987) that i get back from the masked textbox to a date but i get always a value back like 27/12/1988.
So how could I check the given dates with the other dates?
The simple way is to add 18 years to the supplied date and see if the result is today or earlier, e.g.:
// Input date as d/m/y or date object
// Return true/false if d is 18 years or more ago
function isOver18(d) {
var t;
var now = new Date();
// Set hours, mins, secs to zero
now.setHours(0,0,0);
// Deal with string input
if (typeof d == 'string') {
t = d.split('/');
d = new Date(t[2] + '/' + t[1] + '/' + t[0]);
}
// Add 18 years to date, check if on or before today
if (d.setYear && d.getFullYear) {
d.setYear(d.getFullYear() + 18);
}
return d <= now;
}
// For 27/4/2011
isOver18('27/4/2011'); // true
isOver18('26/4/2011'); // true
isOver18('28/4/2011'); // false
try this to start:
var d = new Date(myDate);
var now = new Date();
if ((now.getFullYear() - d.getFullYear()) < 18) {
//do stuff
}
The javascript date object is quite flexible and can handle many date strings.
You can compare two Date objects or use the Date interface methods, such as getSeconds() of getFullYear() in order to deduce useful data regarding the date.
See Date object reference formore details.
You'll need to construct, modify and compare Date objects - something like this:
// str should already be in dd/mm/yyyy format
function parseDate(str) {
var a = str.split('/');
return new Date(parseInt(a[2], 10), // year
parseInt(a[1], 10) - 1, // month, should be 0-11
parseInt(a[0], 10)); // day
}
// returns a date object for today (at midnight)
function today() {
var date = new Date();
date.setHours(0, 0, 0);
return date;
}
function DateInThePast(str) {
// date objects can be compared like numbers
// for equality (==) you'll need to compare the value of date.getTime()
return parseDate(str) < today();
}
function OlderThan18(str) {
// left as an exercise for the reader :-)
}