Why javascript getTime is not a function

Question

I used the following function   function datediff      var dat1   document getElementById  date1   value   alert dat1    i get 2010-04-01 var dat2   document getElementById  date2   value   alert dat2     i get 2010-04-13  var oneDay   24 60 60 1000     hours minutes seconds milliseconds var diffDays   Math abs  dat1 getTime   - dat2 getTime     oneDay    alert diffDays       i get the error dat1 getTime   is not a function

User · Answer

To use this function method you need an instance of the class Date    This method is always used in conjunction with a Date object   See the code below    var d   new Date    d getTime      Link   http   www w3schools com jsref jsref getTime asp

User · Answer

dat1 and dat2 are Strings in JavaScript  There is no getTime function on the String prototype  I believe you want the Date parse   function  http   www w3schools com jsref jsref parse asp  You would use it like this   var date   Date parse dat1

User · Answer

For all those who came here and did indeed use Date typed Variables  here is the solution I found  It does also apply to TypeScript   I was facing this error because I tried to compare two dates using the following Method  var res   dat1 getTime    gt  dat2 getTime       or any other comparison operator   However Im sure I used a Date object  because Im using angularjs with typescript  and I got the data from a typed API call   Im not sure why the error is raised  but I assume that because my Object was created by JSON deserialisation  possibly the getTime   method was simply not added to the prototype   Solution  In this case  recreating a date-Object based on your dates will fix the issue   var res   new Date dat1  getTime    gt  new Date dat2  getTime     Edit   I was right about this  Types will be cast to the according type but they wont be instanciated  Hence there will be a string cast to a date  which will obviously result in a runtime exception   The trick is  if you use interfaces with non primitive only data such as dates or functions  you will need to perform a mapping after your http request   class Details       description  string      date  Date      score  number      approved  boolean       constructor data  any          Object assign this  data             and to perform the mapping   public getDetails id  number   Promise lt Details gt        return this http                 get lt Details gt     this baseUrl  api details   id                    map response   gt  new Details response json                     toPromise        for arrays use   public getDetails    Promise lt Details   gt        return this http                 get lt Details gt     this baseUrl  api details                   map response   gt                       const array   JSON parse response json    as any                       const details   array map data   gt  new Details data                       return details                                    toPromise        For credits and further information about this topic follow the link

User · Answer

That s because your dat1 and dat2 variables are just strings   You should parse them to get a Date object  for that format I always use the following function      parse a date in yyyy-mm-dd format function parseDate input      var parts   input match    d   g        new Date year  month    date    hours   minutes   seconds   ms         return new Date parts 0   parts 1 -1  parts 2       months are 0-based     I use this function because the Date parse string   or new Date string   method is implementation dependent  and the yyyy-MM-dd format will work on modern browser but not on IE  so I prefer doing it manually

[javascript] Why javascript getTime() is not a function?

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