Comments on: How to avoid automatic type conversion in JavaScript http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/ Web development and Internet trends Thu, 20 Nov 2008 10:53:59 +0000 http://wordpress.org/?v=2.6.1 By: Robert Nyman http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-277056 Robert Nyman Mon, 19 May 2008 07:55:25 +0000 http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-277056 Stefan, Yes, it's a great thing to avoid all those weird errors. Berserk, Granted, type checking by default would have been nice, although it's looseness has also made it extremely flexible. I guess it's all about doing the best you can with the tools at hand. Stefan,

Yes, it’s a great thing to avoid all those weird errors.

Berserk,

Granted, type checking by default would have been nice, although it’s looseness has also made it extremely flexible. I guess it’s all about doing the best you can with the tools at hand.

]]> By: Berserk http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-275570 Berserk Sat, 17 May 2008 09:53:21 +0000 http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-275570 One of the causes, as in Andrea's example, is that the same operator is used for addition and concatenation. I find Perl's .-operator much smarter is this kind of circumstances. Of course, in some ways, concatenation can be seen as addition for strings so it makes sense in a semantic way, I guess. One of the causes, as in Andrea’s example, is that the same operator is used for addition and concatenation. I find Perl’s .-operator much smarter is this kind of circumstances. Of course, in some ways, concatenation can be seen as addition for strings so it makes sense in a semantic way, I guess.

]]> By: Stefan Van Reeth http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-275092 Stefan Van Reeth Fri, 16 May 2008 21:21:12 +0000 http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-275092 Since I use JSLint I have no choice but using ===. Which is a good thing. In fact I only used == before reading a similiar post somewhere, and that's now allready a moment far away in the cold mists of time.... Admitted, before that day sometimes I pulled my hairs wondering "wtf". Eternal thx to whoever pointed it out then, and good work Robert on spreading the word. In short: === rocks. Back to the beer ;) Since I use JSLint I have no choice but using ===. Which is a good thing. In fact I only used == before reading a similiar post somewhere, and that’s now allready a moment far away in the cold mists of time….

Admitted, before that day sometimes I pulled my hairs wondering “wtf”. Eternal thx to whoever pointed it out then, and good work Robert on spreading the word.

In short: === rocks. Back to the beer ;)

]]> By: Robert Nyman http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-274872 Robert Nyman Fri, 16 May 2008 15:23:37 +0000 http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-274872 Glad to help! Andrea, Dave, Those are just wonderful! :-) Thanks for pointing them out. Dave, Thanks! Glad to help!

Andrea, Dave,

Those are just wonderful! :-)
Thanks for pointing them out.

Dave,

Thanks!

]]> By: Dave http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-274701 Dave Fri, 16 May 2008 10:10:12 +0000 http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-274701 Can you guess what this equates to: <code>alert('2' * '2' + 1 + '3' + 7);</code> The * converts strings to ints, then the + is used as addition. The '3' means the 2nd + is concatenate, turning it into a string, so the final + 7 is also concatenate. As always, be careful getting ints from the user, and be careful with +. Similar problems in PHP too. PS, Comment preview is very cool. Can you guess what this equates to:
alert('2' * '2' + 1 + '3' + 7);
The * converts strings to ints, then the + is used as addition. The ‘3′ means the 2nd + is concatenate, turning it into a string, so the final + 7 is also concatenate. As always, be careful getting ints from the user, and be careful with +. Similar problems in PHP too.

PS, Comment preview is very cool.

]]> By: Andrea Giammarchi http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-274639 Andrea Giammarchi Fri, 16 May 2008 08:25:38 +0000 http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-274639 My favorite one is this one: <code> alert({toString:function(){return "null"}} == "null"); </code> ;) My favorite one is this one:

alert({toString:function(){return "null"}} == "null");

;)

]]> By: Anthony http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-274634 Anthony Fri, 16 May 2008 08:16:37 +0000 http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-274634 It is indeed a very common problem, which most of the developers I have encountered are sadly not aware of... I tend to "validate" my javascript code with JSLint on a regular basis, and it has already helped me prevent and/or correct a few bugs. Once you know how to configure it, it is really helpful. Thanks for the reminder Robert, I haven't checked my code with JSLint in a while ;-) It is indeed a very common problem, which most of the developers I have encountered are sadly not aware of…
I tend to “validate” my javascript code with JSLint on a regular basis, and it has already helped me prevent and/or correct a few bugs. Once you know how to configure it, it is really helpful.

Thanks for the reminder Robert, I haven’t checked my code with JSLint in a while ;-)

]]> By: Phil Nash http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-274630 Phil Nash Fri, 16 May 2008 08:11:59 +0000 http://www.robertnyman.com/2008/05/16/how-to-avoid-automatic-type-conversion-in-javascript/#comment-274630 Loose typing is one of my favourite things in JavaScript (and any other language I can find it in). Maybe because I expect things to be loose (yeah, you should see me try to program in Java) I don't tend to have problems with them. Good tip though! If this does present a problem, I'll know what to do. Loose typing is one of my favourite things in JavaScript (and any other language I can find it in). Maybe because I expect things to be loose (yeah, you should see me try to program in Java) I don’t tend to have problems with them.

Good tip though! If this does present a problem, I’ll know what to do.

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