twoDigitFloat bug for 568.80

[pedrobelo@…]

twoDigitFloat(568.80) returns "568.79". Just tested in the trunk, too.

In case anyone wants to test this, in test/test_Format.js:

    t.is( twoDigitFloat(568.80), "568.80", "twoDigitFloat 568.80 correct");

[cederberg@…]

Indeed. Thanks for the great test case. I'll look into this asap.

[cederberg@…]

This test also fails:

    t.is( truncToFixed(568.80, 2), "568.80", "truncToFixed 568.80, floating-point error" );

The problem is that 568.80 * 100 becomes 56879.99999999999 in both Safari 3.1 and Firefox 2.0 (the only two I've tested with). Floating-point number commonly show these types of issues, since they use a binary representation instead of the decimal one that we commonly use.

That said, we should probably handle this is some way. Probably avoid multiplications altogether, since they are bound to increase any rounding errors in the internal representation.

[cederberg@…]

Fixed in svn trunk for MochiKit 1.4.