Why you shouldn’t use ‘in’ in javascript

How it worksthe in operator returns true if the specified property is in the specified object. source: MDN So? .. it checks if property exists not the value of it. then what can go wrong ? WhyI always had something against in, mainly because it sounds a bit over promising. The first time I used it I was expecting a behavior more like includes, just because the word “in” is very suggestive to infor

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`'ontouchstart' in window`がブラウザによって違う結果になる話