TypeError: Date is not a constructor

Question

So, I've been making forms for my company for some time now with pretty easy Javascript that has worked for me in the past. However all of a sudden it's kicking out the error: TypeError: Date is not a constructor

The Code:

var Date = this.getField("Text1");
Date.value = util.printd("mm/dd/yyyy",new Date());

It works on all my old forms, but now it won't work on new ones... and I've tried making a new button on an old form - just copying and pasting the code, and then it'll break all the other buttons and spit out the same error.

Running: Windows 7 64-bit with Acrobat XI 11.0.10

Solution 1

The variable Date is hiding the global function Date and causing this error. Because of how scoping works in JS, the inner-most use of a name is the one that matters.

In this case, you declare var Date which becomes the only Date the function knows about. When you assign it a field or text (Date = this.getField...), you hide the global class.

You can rename your variable (I would suggest date, as capital names are typically reserved for types) or explicitly reference new window.Date when you go to construct a new date.

Solution 2

This worked for me:

  var d = new window.Date();

Solution 3

Might be this answer will be helpful in future. I was using below code

var dateTime=new date(); 

But right code is

var dateTime=new Date();

Comments

[Michiel]

Had the same issue using AngularJs. There was a service that was being injected called 'Date'. Renaming the service (if possible) or using window.Date solves the issue.

[jetpackpony]

There is no problem with defining the variable named Date. The problem is that it is a global variable that might be used by many other things on a page. Check @ssube answer for details

[Gass]

I was using var x = new Date(someNumber) in React and it wasn't working. This approach solved my problem. Thanks!