[jQuery] Re: A question for John Resig
On Feb 18, 2:53 pm, pbcomm pbc...@gmail.com wrote: This might be a stupid question, but I have to ask ... What is the reason for not having functions like isString, isNumber, isBoolean, etc? Is it just because that would create extra function calls? The simple reason for me is that typeof tells you the type, it doesn't tell you for certain whether the tested variable is callable or not. Native objects that implement [[call]] must return 'function', however host objects can return any value they like, so: if (typeof foo != 'function') doesn't mean foo isn't callable unless you *know* it is a native object. The same goes for all the other is(whatever) functions. The use of instanceof is not a suitable alternative in a general sense as it doesn't work across frames. -- Rob
[jQuery] Re: A question for John Resig
I'm curious what the benefit of that would be. Given that the window.undefined property exists and has the undefined value, I'd think they would give the same result. -Mike From: John Resig ...we'll probably switch from foo === undefined to typeof foo === undefined - we'll see
[jQuery] Re: A question for John Resig
I'm curious what the benefit of that would be. Given that the window.undefined property exists and has the undefined value, I'd think they would give the same result. They give the same results for properties, at least: someObject.undefinedProperty === undefined but not for variables that are undefined (meaning that 'var someUndefinedVar' or 'window.someUndefinedVar' was not used): someUndefinedVar === undefined // error typeof someUndefinedVar === undefiend // works I think it'd be better to be consistent everywhere. --John
[jQuery] Re: A question for John Resig
Thanks for clearing that up John. -Trey On Feb 19, 10:07 am, John Resig jere...@gmail.com wrote: Why implement jQuery.isFunction when you can also just go typeof variable == 'function'? You can see some of the cases that we handle that normal typeof can't, here:http://dev.jquery.com/browser/trunk/jquery/test/unit/core.js#L176 --John
[jQuery] Re: A question for John Resig
Extra function calls sure - plus there's really no need for those methods, they're already a part of JavaScript. typeof FOO === string typeof FOO === number typeof FOO === boolean --John On Tue, Feb 17, 2009 at 11:53 PM, pbcomm pbc...@gmail.com wrote: This might be a stupid question, but I have to ask ... What is the reason for not having functions like isString, isNumber, isBoolean, etc? Is it just because that would create extra function calls?
[jQuery] Re: A question for John Resig
I know they are there and I've used added functions to save on the code size, which makes a big difference when used a lot. That's why I wanted to see if there are some other drawbacks I was not aware of. On Feb 18, 7:57 am, John Resig jere...@gmail.com wrote: Extra function calls sure - plus there's really no need for those methods, they're already a part of JavaScript. typeof FOO === string typeof FOO === number typeof FOO === boolean --John On Tue, Feb 17, 2009 at 11:53 PM, pbcomm pbc...@gmail.com wrote: This might be a stupid question, but I have to ask ... What is the reason for not having functions like isString, isNumber, isBoolean, etc? Is it just because that would create extra function calls?
[jQuery] Re: A question for John Resig
I know they are there and I've used added functions to save on the code size, which makes a big difference when used a lot. It doesn't make any difference save for a few characters.
[jQuery] Re: A question for John Resig
I don't know about Javascript, but a good deal depends on how that functionality is implemented, and what language you're in. They're not always the same thing, and shouldn't always be used like they are the same thing. Again though, they may be in Javascript, i'm not saying they're not. (I'm not really a javascript expert) In the Java language, for example, you have the instanceof operator. This is fine if you only need to check the type of something only a few times, but if it's a several times per unit time kinda thing, you start to run into efficiency problems. So using methods that make use of more efficient algorithms become the better way to go. cheers Michael Lawson Content Tools Developer, Global Solutions, ibm.com Phone: 1-919-517-1568 Tieline: 255-1568 E-mail: mjlaw...@us.ibm.com 'Examine my teachings critically, as a gold assayer would test gold. If you find they make sense, conform to your experience, and don't harm yourself or others, only then should you accept them.' From: Aleem B ale...@gmail.com To: jquery-en@googlegroups.com Date: 02/18/2009 08:36 AM Subject:[jQuery] Re: A question for John Resig I know they are there and I've used added functions to save on the code size, which makes a big difference when used a lot. It doesn't make any difference save for a few characters. inline: graycol.gifinline: ecblank.gif
[jQuery] Re: A question for John Resig
Matt, While it would not affect the results, I believe you can shave a few ms off by using === On Feb 18, 11:26 am, Matt Kruse m...@thekrusefamily.com wrote: On Feb 18, 6:57 am, John Resig jere...@gmail.com wrote: typeof FOO === string typeof FOO === number typeof FOO === boolean == is sufficient. typeof always returns a string. Matt Kruse
[jQuery] Re: A question for John Resig
On Feb 18, 2:20 pm, Kean shenan...@gmail.com wrote: While it would not affect the results, I believe you can shave a few ms off by using === Over 10,000,000 iterations, I see no difference in time between using == and ===. If the return type of 'typeof' varied, a difference might be found. It's just a minor quibble anyway. It's similar to lines like this in the jquery source: if ( typeof text !== object text != null ) Fixing things like this would tighten and improve the code a bit, IMO. Matt Kruse
[jQuery] Re: A question for John Resig
Seems like my hunch is incorrect, thanks for correcting. On Feb 18, 12:43 pm, Matt Kruse m...@thekrusefamily.com wrote: On Feb 18, 2:20 pm, Kean shenan...@gmail.com wrote: While it would not affect the results, I believe you can shave a few ms off by using === Over 10,000,000 iterations, I see no difference in time between using == and ===. If the return type of 'typeof' varied, a difference might be found. It's just a minor quibble anyway. It's similar to lines like this in the jquery source: if ( typeof text !== object text != null ) Fixing things like this would tighten and improve the code a bit, IMO. Matt Kruse
[jQuery] Re: A question for John Resig
Why implement jQuery.isFunction when you can also just go typeof variable == 'function'? -T On Feb 19, 7:54 am, Kean shenan...@gmail.com wrote: Seems like my hunch is incorrect, thanks for correcting. On Feb 18, 12:43 pm, Matt Kruse m...@thekrusefamily.com wrote: On Feb 18, 2:20 pm, Kean shenan...@gmail.com wrote: While it would not affect the results, I believe you can shave a few ms off by using === Over 10,000,000 iterations, I see no difference in time between using == and ===. If the return type of 'typeof' varied, a difference might be found. It's just a minor quibble anyway. It's similar to lines like this in the jquery source: if ( typeof text !== object text != null ) Fixing things like this would tighten and improve the code a bit, IMO. Matt Kruse
[jQuery] Re: A question for John Resig
It really depends in which browser you test. I'm seeing little to no difference in IE and Firefox - but a noticeable difference in Safari and Opera. http://dev.jquery.com/~john/ticket/equals/ Safari: +3ms, +2ms, +7ms, +3ms, +4ms Opera: +46ms, +35ms, +21ms, +19ms, +36ms (over 500,000 iterations) It's not massive, but it's measurable. As far is its use - I see no problem with it. It's more precise and instills good habits (being more precise about what you want to target). I also see no problem with this: if ( typeof text !== object text != null ) We want items that aren't objects, aren't null, and aren't undefined. Looks fine to me. As far as convention, we're already working to formalize it: http://docs.jquery.com/JQuery_Core_Style_Guidelines It's very basic right now (and we'll probably switch from foo === undefined to typeof foo === undefined - we'll see) but it's a work in progress. --John On Wed, Feb 18, 2009 at 3:43 PM, Matt Kruse m...@thekrusefamily.com wrote: On Feb 18, 2:20 pm, Kean shenan...@gmail.com wrote: While it would not affect the results, I believe you can shave a few ms off by using === Over 10,000,000 iterations, I see no difference in time between using == and ===. If the return type of 'typeof' varied, a difference might be found. It's just a minor quibble anyway. It's similar to lines like this in the jquery source: if ( typeof text !== object text != null ) Fixing things like this would tighten and improve the code a bit, IMO. Matt Kruse
[jQuery] Re: A question for John Resig
Why implement jQuery.isFunction when you can also just go typeof variable == 'function'? You can see some of the cases that we handle that normal typeof can't, here: http://dev.jquery.com/browser/trunk/jquery/test/unit/core.js#L176 --John
[jQuery] Re: A question for John Resig
Safari: +3ms, +2ms, +7ms, +3ms, +4ms Opera: +46ms, +35ms, +21ms, +19ms, +36ms I forgot to mention that this means that == is about 10% slower than === in both browsers. --John
[jQuery] Re: A question for John Resig
lol, i can see this kind of took a different route ;) thank you all for replying ;) On Feb 18, 6:25 pm, John Resig jere...@gmail.com wrote: Safari: +3ms, +2ms, +7ms, +3ms, +4ms Opera: +46ms, +35ms, +21ms, +19ms, +36ms I forgot to mention that this means that == is about 10% slower than === in both browsers. --John
