Want to know why "prop in obj" is slower than "obj.prop !== undefined" in SpiderMonkey? Great overview by @bz_moz: https://lists.mozilla.org/pipermail/dev-tech-js-engine-internals/2014-July/001858.html …
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Replying to @fitzgen
@fitzgen@angelinamagnum@bz_moz worth noting, results can vary... var a={}; a.b = undefined; 'b' in a; // true a.b !== undefined; // false3 replies 0 retweets 0 likes -
Replying to @angustweets
@angustweets@fitzgen@angelinamagnum The main lesson here, really, is that microbenchmarks will lie to you unless you're really careful.1 reply 2 retweets 2 likes -
Replying to @really_bz
@bz_moz@fitzgen@angelinamagnum agree totally, and love your insight. Just wanted to add a note of caution for people who do a blanket swap1 reply 0 retweets 0 likes
Replying to @angustweets
@angustweets @fitzgen @angelinamagnum Oh, God, yes. Please do NOT use microbenchmark results to blanket-swap things!
11:18 AM - 30 Jul 2014
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