firebug fails to report error like “if(maxi - 1 = i)…”

Question

I missed a "=", should be:

if(maxi - 1 == i)...

but firebug didn't report anything.

And it took quite a while for me to found it.

Is it a bug of firebug?

Answer 1

It works perfectly for me. I am using Firebug v1.4.2. Additional add-ons: Google Page Speed, YSlow, Firecookies

My code:

<script type="text/javascript">
var max = 5;
if(max - 1 = 4){
alert(true);
}
</script>

Screenshot:
screenshot http://img12.imageshack.us/img12/451/21986504.th.jpg

I have a "Invalid assignment left-hand side" error for the example you've provided.

EDIT:
As described by Asker - the error was in a JS file. I've done an include like this. Same thing, the error was also tracked.
screenshot http://img17.imageshack.us/img17/8462/31594029.th.jpg

Conclusion
I think its that, when you load the page, Firebug is not activated. When you activate after page has loaded, the error was not captured. Thus you see no error. If you keep Firebug activated and open the page, you might just see the error logged.

Hope this helps!

Answer 2

Firebug is not necessarily the be-all-end-all of code problems. It is only a tool to help you find bugs. It's impossible to write a tool to find every single bug in a program (if only...).

Answer 3

To be fair, nothing in your toolbox found it -- why place the blame only on Firebug? You missed it, your text editor missed it, and your unit tests missed it, at least.

For example, if I type that expression in my editor, it's underlined in orange, and the status bar says:

Test for equality (==) mistyped as assignment (=)? (parenthesize to suppress warning)

Why wait until your code gets to your web browser to see if it worked? There are many steps before that which are great for verification and testing. The sooner you identify problems, the easier they are to fix.