lastIndexOf not returning correct result

[johnysusanto]

I found this bug while working with jQuery plugin named mentionsinput (http://podio.github.com/jquery-mentions-input/).

Basically the lastIndexOf call is not picking up the correct index ( it's always giving back -1 ).

The line is as below, found under checkTriggerChar() :
var triggerCharIndex = _.lastIndexOf(inputBuffer, triggerChar);

I had to switch to the native Javascript lastIndexOf() to get around it at this point.
Seems like this is happening since the new 1.4.

[jashkenas]

I don't believe the behavior of lastIndexOf has changed significantly, other than to now support a fromIndex third argument. Do you have a stand-alone failing test case you can provide?

[jdalton]

Imma guess it's the fromIndex being passed as undefined that's getting converted to 0 which would cause it to fail.

[jdalton]

Yap. The spec outlines it here: http://es5.github.com/#x15.4.4.15

[jashkenas]

Ugh -- there was no basic test for lastIndexOf. Fixed above. I'll push out a patch release by the end of the day, with any other regressions that may arise.