Hi, The following jsperf microbenchmark suggests that |p in o| is much slower than |o.p !== undefined|: http://jsperf.com/in-vs-not-undefined
Can someone explain why? http://stackoverflow.com/questions/13866442/why-is-javascripts-in-operator-consistently-slower-than-strict-member-compari discusses this, but I'm not entirely convinced. Maybe the ToString() required for 'in' explains it? Thanks. Nick _______________________________________________ dev-tech-js-engine-internals mailing list [email protected] https://lists.mozilla.org/listinfo/dev-tech-js-engine-internals
