SpiderMonkey Bug?

[Capt. Murphy]

Hi,

Scenario 1

x = 110.0678
y = 120.0789

x = x.toFixed(2)
y= y.toFixed(2)

x<=y returns true as expected.

Scenario 2

x = 90.0678
y = 120.0789

x=x.toFixed(2)
y=y.toFixed(2)

x<=y returns false which appears to be a bug that occurs when the numbers have a different number of leading digits. I know that toFixed returns a string rather than a number, but shouldn't SpiderMonkey be converting the values to numbers on the fly?

Workaround is

parseFloat(x)<=parseFloat(y)

which returns true as it should in both situations.

or alternatively to

x= Number(x.toFixed(2))
y= Number(y.toFixed(2))

in which case x<=y returns the expected value in both situations.

[Eric Walch]

x<=y returns false which appears to be a bug that occurs when the numbers have a different number of leading digits. I know that toFixed returns a string rather than a number, but shouldn't SpiderMonkey be converting the values to numbers on the fly?

No, when both variables are of type string, SpiderMonkey sees no reason to do a string conversion.

This is a more general bug of string comparisons algorithms. When I sort on files by name, I also get the order:

Code: Select all

file1
file10
file2

Im sure there is a hook to fix that, as with the classic mac operating system, I had a system tool that changes the string sorting order so the files were correctly sorted as:

Code: Select all

file1
file2
file10

I have no idea why that is not the default string sorting order and I would like to have this behaviour back with OSX10 I am sure that when you could add custom string sort routines in classic mac os, this must also be possible in the current os.

[Capt. Murphy]

No, when both variables are of type string, SpiderMonkey sees no reason to do a string conversion.

Thanks Eric, that makes sense and matches what the MDN documentation says when I read it properly.

[Kaks]

There's an old js 'trick' to make sure a number-like object is actually a number.
In this case you could have:

Code: Select all

x.toFixed(2)-0<=y.toFixed(2)-0

Ah, the magic of minus zero!

[Cody]

Ah, the magic of minus zero!

Love Minus Zero/No Limit... a fine old song!