2945Re: [jslint] Re: How to add expection for "Use '===' to compare directly with undefined." error
- Jul 25, 2012How can I avoid ReferenceError for cases like:
var bar = (foo !== undefined) && foo.bar;
var bar = (typeof foo !== 'undefined') && foo.bar;
works in this case.
On Wed, Jul 25, 2012 at 11:47 AM, douglascrockford <douglas@...>wrote:
> --- In email@example.com, Jordan Harband <ljharb@...> wrote:
> > I found http://jsperf.com/typeof-vs-undefined-check/3 awhile back which
> shows that `typeof foo === "undefined"` is faster in some browsers and
> slower in others.
> I do not recommend selecting programming features based on insignificant
> performance findings.
> > Given that "undefined" can be redefined in older browsers, what reasons
> remain for warning on checking undefined with typeof? The only other thing
> you've implied is that people don't redefine undefined. Obviously you may
> pick whichever defaults you like. Since it's possible to redefined
> undefined, however, would you please add a "tolerate" option for this? It
> would be appreciated.
> Such a mishaps has never been reported. It is fixed in ES5. JSLint does
> not allow it.
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