I would like to subclass the built-in Date object to get additional
functionality out of it, but the code below gives me an error
something like "object is not a date object". Is there something I'mm
doing wrong?
function foo() {
}
foo.prototype=n ew Date();
alert( new foo().getHours( ) );
--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome. 4 1841
Christopher Benson-Manica wrote: I would like to subclass the built-in Date object to get additional functionality out of it, but the code below gives me an error something like "object is not a date object". Is there something I'mm doing wrong?
function foo() { } foo.prototype=n ew Date(); alert( new foo().getHours( ) );
The ECMAScript specification says clearly:
15.9.5 Properties of the Date Prototype Object
The Date prototype object is itself a Date object (its [[Class]] is
"Date") whose value is NaN.
The value of the internal [[Prototype]] property of the Date prototype
object is the Object prototype
object (15.2.3.1).
In following descriptions of functions that are properties of the Date
prototype object, the phrase “this
Date object” refers to the object that is the this value for the
invocation of the function. None of these
functions are generic; a TypeError exception is thrown if the this value
is not an object for which the
value of the internal [[Class]] property is "Date".
so an implementation is supposed to throw an error if you try to call a
method like getHours on an object that is not a Date object.
Perhaps it suffices for you if you extend Date e.g.
Date.prototype. yourMethod = function (...) { ... };
--
Martin Honnen http://JavaScript.FAQTs.com/
Martin Honnen <ma*******@yaho o.de> spoke thus: so an implementation is supposed to throw an error if you try to call a method like getHours on an object that is not a Date object.
I suppose that explains why Google didn't help - thank you.
Perhaps it suffices for you if you extend Date e.g.
Date.prototype. yourMethod = function (...) { ... };
Yes, it probably will do...
--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.
JRS: In article <cu**********@c hessie.cirr.com >, dated Fri, 4 Feb 2005
17:26:18, seen in news:comp.lang. javascript, Christopher Benson-Manica
<at***@nospam.c yberspace.org> posted : I would like to subclass the built-in Date object to get additional functionalit y out of it,
Read the newsgroup FAQ, and thereby find js-date8.htm "Enhancing the
Object." In that, Day-of-Year and Julian Date methods are added. It
would probably be more useful to add ISO 8601 week number methods (week
number code is in js-date7.htm), and some I/O (done in include3.js).
but the code below gives me an error something like "object is not a date object". Is there something I'mm doing wrong?
That seems a reasonable deduction.
function foo() { } foo.prototype= new Date(); alert( new foo().getHours( ) );
Basic ISO 8601 week number methods now added to js-date8.htm. Test!
Note : to get Y M D h m s out of a Date Object, as numbers, one uses six
methods; much of the work is repeated six times. It might be possible
to add cacheing versions of output methods, which retain their last
output and the valueOf used for it. When called, if valueOf matches
cache then return previous result, else call standard method and cache
the result.
--
John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 IE 4
<URL:http://www.jibbering.c om/faq/> JL/RC: FAQ of news:comp.lang. javascript
<URL:http://www.merlyn.demo n.co.uk/js-index.htm> jscr maths, dates, sources.
<URL:http://www.merlyn.demo n.co.uk/> TP/BP/Delphi/jscr/&c, FAQ items, links.
Dr John Stockton <sp**@merlyn.de mon.co.uk> spoke thus: Read the newsgroup FAQ,
Ugh, sorry for not having done so. My apologies!
Note : to get Y M D h m s out of a Date Object, as numbers, one uses six methods; much of the work is repeated six times. It might be possible to add cacheing versions of output methods, which retain their last output and the valueOf used for it. When called, if valueOf matches cache then return previous result, else call standard method and cache the result.
I may try that sometime when I have free time...
--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: Gerry Sutton |
last post by:
Hi All!
I have noticed a strange behavior when using a constant identifier to
initialize an instance list variable in a base class and then trying to
modifying the list in subclasses by using either the list.extend method or
even by having the subclass create a whole new list in the variable.
The following example illustrates the situation.
|
by: Robert Scarborough |
last post by:
I have a Table in a Typed Dataset which contains a Date field called
EventDate.
I've ensured that the field is defined as Date as opposed to DateTime in the
Typed Dataset.
When I generate an xml file from an instance of this typed dataset using the
ds.WriteXml method, all the dates come out formatted as follows:
<EventDate>2004-01-26T00:00:00.0000000-05:00</EventDate>
|
by: Lou Pecora |
last post by:
I've been scanning Python in a Nutshell, but this seems to be either
undoable or so subtle that I don't know how to do it.
I want to subclass a base class that is returned from a Standard Library
function (particularly, subclass file which is returned from open). I
would add some extra functionality and keep the base functions, too.
But I am stuck.
E.g.
|
by: s.lipnevich |
last post by:
Hi All,
Is anything wrong with the following code?
class Superclass(object):
def __new__(cls):
# Questioning the statement below
return super(Superclass, cls).__new__(Subclass)
class Subclass(Superclass):
pass
|
by: damacy |
last post by:
hi, there. i have a problem writing a program which can obtain ip
addresses of machines running in the same local network.
say, there are 4 machines present in the network; , , and
and if i run my program on , it should be able to find "host names"
and "ip addresses" of the other machines; , and ?
i have read some threads posted on this group, however, they only work
for localhost, not the entire network.
| |
by: davidfinance |
last post by:
Ok, maybe this is a stupid question, but why can't I make a subclass of
datetime.date and override the __init__ method?
---
from datetime import date
class A(date):
def __init__(self, a, b, c, d):
print a, b, c, d
|
by: Me |
last post by:
I need to be able to acces non-virtual members of sublcasses via a
base class pointer...and without the need for an explicit type cast.
I thought a pure virtual getPtr() that acts as a type cast would solve
the problem, but it appears not to.
I need this functionality to make object serialization a reality. Having
to explicitly cast each deserialized object to its original type defeats
the purpose of my serializing the blasted things in...
|
by: Kurt Smith |
last post by:
Hi List:
Class inheritance noob here.
For context, I have the following base class and subclass:
class Base(object):
def __init__(self, val):
self.val = val
|
by: Christian Heimes |
last post by:
Rick King schrieb:
datetime.date is a C extension class. Subclassing of extension classes
may not always work as you'd expect it.
Christian
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, well explore What is ONU, What Is Router, ONU & Routers main usage, and What is the difference between ONU and Router. Lets take a closer look !
Part I. Meaning of...
|
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it.
First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
| |
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth.
The Art of Business Website Design
Your website is...
|
by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
|
by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome a new presenter, Adolph Dupr who will be discussing some powerful techniques for using class modules.
He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms.
Adolph will...
|
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one.
At the time of converting from word file to html my equations which are in the word document file was convert into image.
Globals.ThisAddIn.Application.ActiveDocument.Select();...
|
by: 6302768590 |
last post by:
Hai team
i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
| |
by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
| |